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DETERMINATION  OF  RADICLES 


IN 


CARBON   COMPOUNDS. 


BY 


Dr.    H.    MEYER, 

Docent  and  Adjunct  of  the 
Imperial  and  Royal  German  University,  Prague. 


AUTHORIZED  TRANSLATION 
BY 

J.  BISHOP  TINGLE,  Ph.D.,  F.C.S., 

Instructor  of  Chemistry  at  the  Lewis  Institute, 
Chicago,  III. 


FIRST   EDITION. 
FIRST    THOUSAND. 


NEW  YORK: 
JOHN    WILEY   &   SONS. 
London  :    CHAPMAN    &   HALL,   Limited. 
1899. 

LIBRARY 

^UNIVERSITY  OF  CALIFORNIA 
DAVIS 


Copyright,  1899, 

BY 

BISHOP  TINGLE. 


ROBERT  DRUMMOND,    PRINTER,  NEW  YORK, 


AUTHOR'S  PREFACE. 


This  English  edition  of  my  "  Anleitung  zur  quanti- 
tativen  Bestimmung  der  organischen  Atomgruppen  " 
has  been  prepared  by  Dr.  J.  Bishop  Tingle,  to  whom  I 
am  greatly  indebted  for  the  care  he  has  bestowed  on 
it.  I  have  endeavored  to  bring  it  into  conformity 
with  the  present  state  of  the  science  by  various  cor- 
rections and  additions.  It  has  been  further  improved 
by  certain  changes  in  arrangement  which  Dr.  Tingle 
has  made,  and  he  has  also  added  various  notes.  The 
present  edition  is  thus  a  decided  advancement  on  the 
German  one,  and  I  trust  that  in  its  new  form  it  may 
gain  many  new  friends  whilst  retaining  its  old  ones. 

Dr.  Hans  Meyer. 

Prague,  October  1899. 

iii 


TRANSLATOR'S  PREFACE. 


THE  success  of  the  German  edition  of  Dr.  Meyer's 
book  was  only  one  of  the  reasons  that  led  to  the  prep- 
aration of  this  translation.  The  quantitative  side  of 
organic  chemistry,  apart  from  elementary  analysis,  is 
almost  always  neglected  in  the  ordinary  courses  of  in- 
struction, and  when  the  need  for  it  arises,  in  the  pros- 
ecution of  research  work  for  instance,  it  is  difficult  to 
obtain  a  comprehensive  view  of  the  methods  which  are 
available  without  undue  expenditure  of  time.  This 
little  work  supplies,  for  the  first  time,  a  systematic 
treatment  of  these  methods  which,  it  is  hoped,  may 
help  to  remove  this  drawback  and  may  also  encour- 
age the  introduction  of  some  quantitative  work  into 
the  college  courses  of  organic  preparations,  since  such 
a  departure  could  scarcely  fail  to  be  beneficial  in 
various  ways  to  the  student.  From  the  translator's 
experience  with  the  German  edition  he  believes  that 
the  present  one  will  be  serviceable  to  instructors  and 
senior  students  of  organic  chemistry.  Considerable 
care  has  been  bestowed  on  the  proof-sheets,  and  it  is 
hoped  that  the  errors  which  may  have  escaped  notice 
are  not  too  glaring. 

Lewis    Institute,  Chicago,  III., 
October  1899. 


CONTENTS. 


CHAPTER    I. 

I  PAGE 

Introductory.     Determination  of  Hydroxyl,  OH i 

Introductory,  I.  Determination  of  hydroxyl,  3.  Acy- 
lation,  3.  Preparation  of  acetyl  derivatives,  5.  (A)  By 
acetyl  chloride,  5.  (B)  By  acetic  anhydride,  7.  (C)  By 
glacial  acetic  acid,  8.  Isolation  of  acetyl  derivatives,  9. 
Determination  of  the  acetyl  groups,  9.  (A)  Hydrolytic 
methods,  9.  (B)  Additive  method,  14.  (C)  Potassium 
acetate  method,  14.  (D)  Distillation  method,  15.  Ben- 
zoyl derivatives,  17.  (A)  Preparation  from  benzoyl 
chloride,  18.  (B)  Preparation  from  benzoic  anhydride, 
21.  Preparation  of  substituted  benzoic  acid  deriva- 
tives and  of  phenylsulphonic  chloride,  22.  Acylation 
by  means  of  substituted  benzoic  acid  derivatives  and 
of  phenylsulphonic  chloride,  23.  Analysis  of  benzoyl 
derivatives,  24.  Acylation  by  means  of  other  acid  rad- 
icles, 27.  Alkylation  of  hydroxyl  groups,  28.  Prepara- 
tion of  benzyl  derivatives,  28.  Preparation  of  carba- 
mates by  means  of  carbamyl  chloride,  29.  Preparation 
of  diphenylcarbamyl  chloride,  30.  Preparation  of  phe- 
nylcarbamic  acid  derivatives,  31.  Preparation  of  phenyl- 
isocyanate,  31.  Action  of  phenylisocyanate  on  hydroxyl 
derivatives,  31. 


CHAPTER    II. 

1  1 

Determination  of  Methoxyl,  CH3O-,  Ethoxyl,  CaH60-, 

and  Carboxyl,  CO. OH 33 

Determination    of    methoxyl,    S.    Zeisel's  method,    33. 

vii 


Vlll  CONTENTS. 

paGH 
For  non-volatile  substances,  36.  For  volatile  com- 
pounds, 38.  Modified  method,  39.  Method  for  the 
differentiation  of  methoxyl  and  ethoxyl,  40.  Deter- 
mination of  ethoxyl,  41.  Determination  of  carboxyl, 
41.  (A)  Analysis  of  metallic  salts,  42.  (B)  Titra- 
tion of  acids,  43.  (C)  Etherification,  44.  (D)  Elec- 
trolytic conductivity  of  sodium  salts,  46.  Indirect  meth- 
ods for  the  determination  of  the  basicity  of  acids,  51.  (i) 
Carbonate  method,  51.  (ii)  Ammonia  method,  52.  (iii) 
Hydrogen  sulphide  method,  52.  (iv)  Iodine-oxygen 
method,  57. 

CHAPTER    III. 

Det  ermination  of  Carbonyi 60 

Preparation  of  phenylhydrazones,  60.  Preparation  of 
substituted  hydrazones  and  of  parabromophenylhydra- 
zine,  63.  Indirect  method,  65.  Preparation  of  oximes, 
70.  Preparation  of  semicarbazones,  74,  77.  Preparation 
of  semicarbazide  salts,  75.  Preparation  of  amidoguani- 
dine  derivatives,  78.  Paramidodimethylaniline  deriva- 
tives, 80. 


CHAPTER    IV. 

Determination  of  the  amino  group,  81.  Determination 
of  aliphatic  amines  (i)  nitrous  acid  method,  81.  (ii)  Anal- 
ysis of  salts  and  double  salts.  82.  (iii)  Acetylation,  83. 
Determination  of  aromatic  amines:  (i)  Titration' of  the 
salts,  83.  (ii)  Preparation  of  diazo-derivatives:  {a)  con- 
version into  an  azo  dye,  84.  {b)  Indirect  method,  85. 
(c)  Azoimide  method,  86.  (d)  Sandmeyer-Gattermann's 
reaction,  87.  (iii)  Analysis  of  salts  and  double  salts,  89. 
(iv)  Acetylation,  89.  Determination  of  the  nitrile  group, 
90.  Determination  of  the  amido  group,  91.  Determi- 
nation of  the  imide  group:  (i)  Acetylation,  92.  (ii)  Alky- 
lation,  93.  (iii)  Analysis  of  salts,  94.  (iv)  Elimination 
of  imidogen  as  ammonia,  94.  Determination  of  methyl 
imide,  94.  Determination  of  ethyl  imide,  99.  Differ- 
entiation of  the  methyl  imide  and  ethyl  imide  groups,  99. 


CONTENTS.  IX 


CHAPTER   V. 

PAGE 

Determination  of  the  diazo-group  (A)  Aliphatic 
diazo-compounds  :  (i)  Titration  with  iodine,  ioo.  (ii) 
Analysis  of  the  iodine  derivative,  ioi.  (iii)  Determina- 
tion of  the  nitrogen  in  the  wet  way,  ioi.  (B)  Aromatic 
diazo-compounds.  Diazonium  derivatives,  103.  Deter- 
mination of  the  hydrazide  group,  103.  (i)  By  oxidation, 
104.  (ii)  Iodometric  method,  106.  Determination  of  the 
nitrogroup.  (A)  Titration  method,  106.  (i)  Method  for 
non-volatile  compounds,  108.  (ii)  Modifications  for  vola- 
tile compounds,  10S.  (B)  Diazo-method,  109.  Determi- 
nation of  the  iodoso-  and  iodoxy-groups,  109.  Deter- 
mination of  the  peroxide  group,  no.  The  iodine  number, 
in.  Appendix.  Table  of  the  weights  of  a  cubic  centi- 
meter   of    hydrogen,    116.      Tension    of    aqueous    vapor, 

118.     Table    for   the  value    of    ,   118.     Index  of 

1000  —  a 

authors,  121.     Index  of  subjects,  129. 


ABBREVIATIONS. 

The  following  abbreviations  have  been  used  in  the 
bibliographical  references : 

Am.  Chem.  Journ.  American  Chemical  Journal. 

Ann.  Liebig's  Annalen  der  Chemie  und  Pharmacie. 

Ann.  de  Ch.  Ph.  Annales  de  Chimie  et  de  Physique. 

Arch.  Pharm.  Archiv  der  Pharmacie. 

B.  Berichte    der   Deutschen  chemischen  Gesell- 

schaft. 
Bull.  Bulletins  de  la  Societe  Chimique  de  Paris. 

C.  Chemisches  Centralblatt. 
Ch.  R.  Chemische  Revue. 

Ch.  Ztg.  Chemiker-Zeitung. 

Ch.  N.  Chemical  News. 

C.  r.  Comptes  rendus  de  l'Academie  des  sciences 

(Paris). 
Dingl.  Dingler's  polytechnisches  Journal. 

Gazz.  Gazzetta  chimica  italiana. 

H.  Beilstein,  Handbuch. 

J.  Jahresbericht      uber      die      fortschritte     der 

Chemie. 
J.  Am.  Journal  of  the  American  Chemical  Society. 

Journ.  Chem.  Soc.     Journal  of  the  Chemical  Society  of  London. 
J.  pr.  Journal  fur  praktische  Chemie. 

M.  Monatshefte  ftlr  Chemie. 

M.  &  J.  V.   Meyer   and   P.  Jacobson,   "  Lehrbuch  der 

organischen  Chemie." 
Rec.  Recueil  des  travaux  chimiques  des  Pays-Bas. 

S.  Seelig,     "  Organische    Reaktionen    und    Re- 

agentien." 
W.  Ann.  Wiedemann's      Annalen      der      Physik     und 

Chemie. 
Z.  Zeitschrift  fur  physikalische  Chemie. 

Z.  An.  Zeitschrift  fur  anorganische  Chemie. 

Z.  anal.  Zeitschrift  fur  analytische  Chemie. 

Z.  ang.  Ch.  Zeitschrift  fiir  angewandte  Chemie. 

Z.  f.  Ch.  Zeitschrift  flir  Chemie. 

Z.  physiol.  Ch.  Zeitschrift  fiir  physiologische  Chemie. 

Z.  Rub.  Zeitschrift    des    Vereines    fiir    Riibenzucker- 

industrie. 


DETERMINATION   OF   RADICLES   IN 
CARBON   COMPOUNDS. 


Chapter  T. 

INTRODUCTORY.      DETERMINATION   OF 
HYDROXYL   (-OH). 

THE  quantitative  analysis  of  inorganic  compounds, 
as  usually  performed,  consists  almost  exclusively  in 
the  determination  of  ions,  since  in  the  present  state  of 
the  science  this  generally  suffices  for  the  identification 
of  the  substance ;  but  to  attain  the  same  end  in  the 
case  of  organic  bodies  the  elementary  analysis  re- 
quires supplementing  by  other  methods.  The  per- 
centage composition  gives  no  information  about  the 
relative  arrangement  of  the  atoms  in  the  molecule, 
but  the  demand  for  methods  of  analysis  which  will 
yield  such  knowledge  increases  with  our  growing  in- 
sight into  the  constitution  of  carbon  compounds. 
To  supply  this  want  certain  "quantitative  reactions" 
have  been  applied  for  the  determination  of  special 
groups  of  atoms ;  they  are  widely,  but  almost  exclu- 
sively, employed  by  technologists  in  the  analysis  of 
such  substances  as  fats,  waxes,  resins,  ethereal  oils, 
caoutchouc,    glue,    paper,    etc.,    and   the   results  are 


2  RADICLES   IN   CARBON   COMPOUNDS. 

known  as  the  "acid  number,"  "saponification  num- 
ber," "iodine  number,"  "methoxyl  number,"  "  ace- 
tyl number,"  "  carbonyl  number,"  etc.  The  deter- 
mination of  such  "numbers"  or  "  values"  obtained 
by  the  action  of  some  reagent  on  a  known  weight 
of  substance  is  frequently  insufficient  for  scientific 
investigation,  this  renders  it  necessary  to  work 
out  a  special  process  for  each  group  of  organic  com- 
pounds in  order  to  determine  the  radicles  which  are 
present. 

The  reactions  of  organic  compounds  are  only  in 
part  ionic ;  usually  they  are  conditioned  by  the  con- 
figuration and  state  of  equilibrium  of  the  molecule, 
and  consequently  a  reaction  which  readily  occurs  with 
one  compound  may  totally  fail  with  another  of  very 
similar  constitution  on  account  of  stereoisomerism  ;  or, 
by  substitution,  a  radicle  may  approximate  more  or 
less  closely  to  the  character  and  functions  of  another 
one.  In  these  cases  the  quantitative  separation  of  the 
compounds  is  more  difficult,  and  can  frequently  only 
be  accomplished  by  differences  in  crystallizing  power, 
or  by  the  preparation  of  derivatives  which  can  be 
volatilized  without  decomposition. 

Since  the  course  of  a  particular  reaction  of  an  inor- 
ganic compound  is  only  conditioned  by  the  behavior 
of  the  ions  which  are  to  be  determined,  it  follows  that 
the  analytical  methods  are  in  a  sense  independent  of 
the  nature  of  the  compounds  investigated,  and  conse- 
quently of  very  wide  application.  The  matter  is  far 
otherwise  with  organic  compounds :  there  are  very 
few  processes  which,  like  Ziesel's  method  for  deter- 
mining methoxyl,  can  be  applied  almost  universally. 


DETERMINATION   OF   HYDROXYL.  3 

Usually,  then,  it  becomes  necessary  for  the  analyst 
himself  to  select  the  method  most  appropriate  for 
his  special  purpose,  or,  perhaps  by  a  combination  of 
several,  to  devise  one  which  may  lead  to  the  desired 
result.  The  successful  methods  hitherto  proposed 
for  the  determination  of  organic  radicles  have  been 
collected  together  in  this  work,  and  it  is  hoped  that 
they  may  serve  to  indicate  the  direction  in  which 
research  may  be  successfully  prosecuted  for  the  dis- 
covery of  new  ones  applicable  to  hitherto  unforeseen 
conditions. 

DETERMINATION   OF   HYDROXYL   (-OH). 

The  determination  of  the  hydroxyl  radicle  in  or- 
ganic compounds  consists  in  the  preparation  of  deriva- 
tives by  the  following  methods: 

(I.)  ACYLATION. — This  consists  in  the  introduc- 
tion into  the  hydroxyl  compound  of  the  radicle  of 
one  of  the  acids  mentioned  below: 

Acetic  acid  ; 

Benzoic  acid  and  its  substitution  products ; 

Phenylsulphonic  acid. 
Of  less  frequent  employment  are  the  radicles  of 

Propionic  acid ; 

Isobutyric  acid ; 

Phenylacctic  acid. 

(II.)  ALKYLATION. — Confined  usually  to  the  prep- 
aration of  benzyl  derivatives. 

(III.)  The  preparation  of  CARBAMATES. 

(IV.)  The  formation  of  ESTERS  OF  PHENYLCAR- 
BAMIC   ACID. 


4  RADICLES   IN   CARBON   COMPOUNDS. 

As  a  rule,  attention  is  first  directed  to  the  prepara- 
tion of  an  acetyl  or  benzoyl  derivative,  the  former 
usually  by  Liebermann  &  Hermann's  method  (see 
page  7),  the  latter  by  that  of  Loss'en  or  Schotten- 
Baumann  (see  page  18).  Not  infrequently,  however, 
it  becomes  necessary  to  resort  to  one  of  the  other 
forms  of  procedure  in  order  to  determine  the  consti- 
tution of  the  body  under  investigation.  As  the 
groups  NH„  NH2  and  SH  are  all  capable  of  acylation, 
care  is  required  to  avoid  confusion  if  the  original 
compound  contains  nitrogen  or  sulphur.  Instances 
are  known  of  acetylation  taking  place  in  the  absence 
of  hydroxyl  and  of  the  groups  just  referred  to,  thus 
diacetylhydroquinol  is  formed  from  quinone,  acetic 
anhydride,  and  sodium  acetate;1  tetrachloroquinone 
and  acetyl  chloride  yield  diacetyltetrachlorohydro- 
quinol;3  whilst  pyrogallophthalei'n  (gallein),  which 
contains  only  two  hydroxyl  groups,  forms  a  tetracetyl 
and  tetrabenzoyl  derivative.3  Acetylating  reagents 
frequently  cause  isomerization  or  polymerization,  and 
sometimes  lead  to  the  production  of  anhydrides,  etc.  ; 
thus  benzhydrylacetocarboxylican  hydride  is  obtained 
from  the  isomeric  orthocinnamocarboxylic  acid  by 
the  action  of  acetic  anhydride  and  sodium  acetate,4 
and  cantharic  acid  when  heated  in  a  sealed  tube  with 
acetyl  chloride  yields  isocantharidin.6  In  view  of 
these  and  similar  facts,  care  should  be  taken  to  hydro- 
lyse  the  presumptive  acetyl  derivative  and  identify 
the  product  with  the  original  substance ;   should  this 

'Sarauw,  B.  12,  680.  8  Graebe,  Ann.  146,  13. 

'Buchka,  B.  14,  1327.  4  Benedikt  and  Ehrlich,  M.  9,  529. 


Anderlini  and  Ghiro,  B.  24,  1998. 


DETERMINATION   OF    HYDROXYL.  5 

not  be  possible,  then  proof  must  be  obtained  that  the 
derivative  does  actually  contain  the  acid  radicle,  the 
introduction  of  which  has  been  attempted. 

I.   METHODS  OF  ACETYLATION. 

(i)    PREPARATION    OF   ACETYL   DERIVATIVES. 

The  following  reagents  are  employed  for  the  prepa- 
tion  of  acetyl  derivatives  from  organic  compounds 
containing  hydroxyl  groups: 

(A)  Acetyl  chloride. 

(B)  Acetic  anhydride,  sodium  acetate. 

(C)  Glacial  acetic  acid. 

(D)  Chloracetyl  chloride. 

(A)  Acetylation  by  Means  of  Acetyl  Chloride. 

(a)  Many  hydroxyl  derivatives  react  with  acetyl 
chloride  when  simply  mixed  or  digested  on  the  water- 
bath.  It  is  convenient  to  dissolve  the  substance  and 
the  chloride  in  benzene,  and  boil  the  solution  until 
the  evolution  of  hydrochloric  acid  ceases.  If  there  is 
no  danger  of  the  hydrogen  chloride  causing  secondary 
reactions  (hydrolysis),  of  which  an  interesting  case  has 
been  recorded,1  the  substance  may  be  heated  with  the 
chloride  in  a  sealed  tube  without  solvent.  Certain 
dibasic  hydroxy  acids  of  the  aliphatic  series,  such  as 
mucic  acid,  which  are  not  changed  with  acetyl  chloride 
alone,  frequently  react  with  it  on  the  addition  of  zinc 
chloride.2      In   "general,  it    may  be   stated  that  acetyl 

1  Herzig  and  Schiff,  B.  30,  397.     Cf.  Bamberger  and  Landsiedl, 
M.  18,  307. 
2S.,  p.  258. 


6  RADICLES   IN   CARBON   COMPOUNDS. 

chloride  only  reacts  readily  with  alcohols  and  phenols, 
but,  as  it  may  lead  to  the  production  of  anhydrides 
from  polybasic  acids,  these  are  usually  employed  in 
the  form  of  esters,  which  has  the  additional  advan- 
tage of  yielding  products  that  are  much  more  easily 
distilled  than  the  corresponding  derivatives  of  the 
acids  themselves.1 

(b)  The  following  method  a  is  frequently  more  con- 
venient than  the  "acid"  acetylation  just  described. 
The  substance  is  dissolved  in  ether  or  benzene,  and 
digested  with  the  necessary  quantity  of  acetyl  chloride 
and  dry  alkali  carbonate,  the  latter  being  in  the  pro- 
portion necessary  to  form  a  hydrogen  salt  as  repre- 
sented by  the  equation: 

R.OH  +  CH3.COCI  +  KaCOs  »->  R.O.CO.CH,  + 
KC1  +  KHCO3. 

(c)  Acetylation  by  means  of  acetyl  chloride  and 
aqueous  alkali  is  described  on  p.  20. 

(d)  It  is  often  convenient  to  allow  the  acetyl  chlo- 
ride to  react  with  the  compound  under  investigation 
in  pyridine  solution.3 

(e)  Diacetylacetone  could  only  be  acetylated  by  al- 
lowing its  barium  salt  to  react  with  acetyl  chloride  at 
the  ordinary  temperature.* 

(/)  Instead  of  acetyl  chloride  phosphorus  trichlo- 
ride, or  preferably  the  oxychloride,  or  phosgene  may 
be  employed ;  they  are  allowed  to  react  on  a  mixture 
of  the  substance  and  acetic  acid  in  the  proper  propor- 

'Wislicenus,  Ann.  129,  17.         s  L.  Claisen,  B.  27,  3182. 
8  A.  Deninger,  B.  28,  1322.  4  Feist,  Ibid.  28,  1824. 


DETERMINATION   OF   HYDROXYL.  7 

tion.1  Thus,  for  example,  phenol  is  readily  acety- 
lated  by  heating  it  at  8o°  with  an  equimolecular 
proportion  of  acetic  acid  and  adding  phosphorus  oxy- 
chloride  (J  molecule)  gradually,  by  means  of  a  dropping 
funnel.  When  hydrogen  chloride  is  no  longer  evolved 
the  product  is  poured  into  cold  aqueous  soda  solution  ; 
after  further  washing  with  highly  dilute  alkali  it  is 
treated  once  with  water,  dried  by  means  of  calcium 
chloride,  and  distilled. 

(B)  Acetylation  by  Means  of  Acetic  Anhydride. 

(a)  The  substance  is  usually  boiled  with  5-10  parts 
of  anhydride,  or  heated  with  it  in  a  sealed  tube  during 
several  hours. 

(b)  Not  infrequently  the  substances  must  only  be 
allowed  to  react  during  a  short  time,  at  a  compara- 
tively low  temperature.  Bebirine,  for  instance,  is 
readily  acetylated  when  digested  with  the  anhydride 
during  a  short  time  at  40°-5o°,  but  by  its  prolonged 
action  amorphous  substances  are  formed.3 

(c)  The  substance  may  be  mixed  with  an  equal 
weight  of  dry  sodium  acetate,  and  3-4  parts  of  the 
anhydride,  and  boiled  for  a  short  time  in  a  reflux 
apparatus;3  in  the  case  of  small  quantities  of  substance 
2-3  minutes  boiling  may  suffice.  The  action  ap- 
pears to  depend  on  the  production  of  a  sodium  salt 
of  the  compound  under  examination,  which  then  re- 
acts with  the  anhydride.      This  method  yields,  on  the 

whole,  the   most  trustworthy  results  of  any,  and  sel- 

-*— — c 

1  J.  pr.  25,  282;  26,  62;  31,  467.  5  B.  29,  2057. 

3  C.   Lieberjhann  and  O.  Hormann,  Ibid,  11,  1619. 


8  RADICLES   IN   CARBON   COMPOUNDS. 

dom  fails  to  give  completely  acetylated  derivatives. 
It  fails  in  the  case  of  the  tf-hydroxyl  of  the  hydroxy- 
quinolines,1  though  these  compounds  yield  benzoyl 
derivatives. 

(//)  A  mixture  of  acetic  anhydride  and  acetyl 
chloride  may  be  used,  or  the  action  of  the  anhydride 
may  be  started  by  means  of  a  drop  of  concentrated 
sulphuric  acid.2 

(e)  The  addition  of  zinc  chloride  3  and  of  stannic 
chloride4  has  also  been  recommended. 

(C)  Acetylation  by  Means  of  Glacial  Acetic  Acid. 

Acetylation,  especially  that  of  alcoholic  hydroxyl 
groups,  may  often  be  accomplished  by  heating  the 
substance  with  glacial  acetic  acid,  under  pressure  if 
necessary;  the  addition  of  sodium  acetate  is  also 
advantageous,  and,  in  some  cases,  this  is  the  only 
method  which  gives  the  desired  result.  Thus,  cam- 
phorpinacone  yields  a  chloride  when  treated  with 
acetyl  chloride,  and  is  not  changed  by  boiling  acetic 
anhydride,  but  when  it  is  boiled  .with  glacial  acetic 
acid  for  a  short  time,  a  stable  acetyl  derivative  is 
formed,  and  an  isomeric  "  labile"  one  by  the  action 
of  the  acid  at  the  ordinary  temperature  during 
twenty-four  hours.5 

(D)  Acetylation  by  Means  of  Chloracetyl  Chloride. 

This  reagent  has  also  been  employed  occasionally.8 

1  J.  Diamant,  M.  16,  770.     Cf.  La  Coste  and  Valeur,  B.   20,  1822. 

2  Franchimont,  B.    12,  1941. 

3  Franchimont,  C.  r.  89,  711;  B.  12,2058. 

4  H.  A.  Michael,  B.  27,  2686.  5  Beckmann,  Ann.  292,  17. 

6  Klobukowsky,  B.  10,  881.     Cf.  Ibid.  31,  2790. 


DETERMINATION   OF   HYDROXYL.  9 

II.      ISOLATION    OF    THE    ACETYL 
DERIVATIVES. 

Acetyl  derivatives  are  isolated  by  pouring  the 
product  of  the  reaction  into  water.  The  excess  of 
acetic  acid  may  also  be  removed  by  the  addition  of 
methylic  alcohol  to  convert  it  into  methylic  acetate, 
which  is  then  volatilized ;  residual  acetic  anhydride 
is  separated  by  distillation  under  reduced  pressure. 
Acetyl  derivatives,  soluble  in  water,  may  often  be  pre- 
cipitated by  the  addition  of  solid  sodium  carbonate,  or 
by  extracting  the  solution  with  chloroform  or  benzene. 
Ethylic  acetate  frequently  proves  to  be  an  excellent 
medium  for  the  subsequent  recrystallization  of  the 
acetyl  product. 

III.     DETERMINATION     OF     THE     ACETYL 
GROUPS. 

The  various  acetyl  derivatives  of  a  compound 
usually  differ  little  in  percentage  composition,  so 
that  elementary  analysis  seldom  affords  information 
as  to  the  number  of  acetyl  groups  which  have  entered 
the  original  molecule;  thus,  the  mono-,  di-,  and  tri- 
acetyl  derivatives  of  the  trihydroxybenzenes  have 
an  identical  percentage  composition.  In  such  cases 
the  acetyl  groups  must  be  eliminated  and  the  acetic 
acid  formed  determined  directly  or  indirectly. 

(A)  Hydrolytic  Methods. 

The  following  reagents  are  employed  for  the 
hydrolysis  of  acetyl  compounds : 


IO  RADICLES    IN   CARBON   COMPOUNDS. 

(a)  Water. 

(b)  Potassium  hydroxide,  sodium  hydroxide, 

(c)  Barium  hydroxide. 

(d)  Magnesia. 

(e)  Hydrochloric  acid. 

(f)  Sulphuric  acid. 

(g)  Hydriodic  acid. 

(a)  Some  acetyl  derivatives  are  hydrolysed  by 
heating  with  water  under  pressure;  thus  butenyltri- 
acetin,  C4H7  (C2H302)3,  is  completely  hydrolysed  by 
heating  it  with  forty  parts  of  water  at  1600  in  a  sealed 
tube,  and  the  liberated  acetic  acid  may  be  titrated.1 
Diacetylmorphine  also  loses  one  aceytl  group  by 
boiling  it  with  water,2  and  acetyl  dihydroxypyridine 
is  still  more  unstable.3 

(b)  Hydrolysis  by  means  of  potassium  hydroxide 
or  sodium  hydroxide  is  specially  useful  for  the 
analysis  of  fats.  The  compound  (1-2  grams)  is 
gently  boiled  on  the  water-bath  during  fifteen  min- 
utes, in  a  wide-necked  flask  of  1 00-150  cc  capacity, 
with  alcoholic  potash  (25-50  cc)  of  known  strength, 
which  should  be  about  N/2.  During  the  heating 
the  neck  of  the  flask  is  covered  with  a  cold  funnel ; 
at  the  conclusion  of  the  hydrolysis  phenolphthale'in  is 
added,  and  the  excess  of  alkali  determined  by  means 
of  N/2  hydrochloric  acid.4  The  method  may  also  be 
employed  for  the  determination  of  the  molecular 
weight   of    the  aliphatic   alcohols.     This   is   obtained 

1  Lieben  and  Zeisel,  M.  1,  835. 

8  Wright-Becket,  Journ.  Ch.  Soc.  12,  1033.     Danckwortt,  Arch. 
Pharm.  226,  57. 
3  M.  18,  619.  *  Benedikt  and  Ulzer,  M.  8,  41. 


DETERMINATION   OF   HYDROXYL.  II 

56IOO  . 

from  the  expression  M  =  — ^ 42,  where  M   is  the 

molecular  weight,  and  V  the  number  of  milligrams  of 
potassium  hydroxide  required  to  hydrolyse  1  gram  of 
the  acetyl  derivative.  If  the  compound  is  affected 
by  air,  the  hydrolysis  is  carried  out  in  an  atmos- 
phere of  hydrogen;1  should  the  original  compound 
be  insoluble  in  dilute  hydrochloric  acid,  the  acetyl 
derivative  may  be  boiled  with  aqueous  potash,  the 
product  acidified,  and  the  precipitate  weighed.3 

(c)  Barium  hydroxide  may  be  employed  in  many 
cases  where  potash  causes  decomposition,  thus 
hematoxylin  yields  formic  acid  when  boiled  with 
highly  dilute  alkali,  but  barium  hydroxide  readily 
hydrolyses  its  acetyl  derivatives  without  further 
decomposition.3  One  method  of  procedure4  is  to 
boil  the  compound  under  investigation  with  the 
hydroxide  during  5-6  hours  in  a  reflux  apparatus. 
The  product  is  filtered,  the  filtrate  treated  with  car- 
bonic anhydride  in  excess,  again  filtered,  and  the 
filtrate  evaporated.  The  residue  is  dissolved  in 
water,  the  liquid  filtered,  and,  after  washing,  the 
barium  in  the  filtrate  is  determined  as  sulphate. 
Since  all  the  above  operations  are  conducted  in  glass 
vessels,  some  alkali  from  these  may  neutralize  a  por- 
tion of  the  acetic  acid  and  a  correction  thus  becomes 
necessary.  This  is  obtained  by  concentrating  the 
filtrate  from  the  barium  sulphate  in  a  platinum  dish; 

1  Klobukowsky,  B.  10,  882. 

2Vortmann,   "Anleitung  zur  chemischen  Analyse  organischer 
Stoffe,"  p.  59. 

8  Erdmann  and  Schultz,  Ann.  216,  234.  •  Herzig,  M.  5,  86. 


12  RADICLES   IN  CARBON   COMPOUNDS. 

when  the  excess  of  sulphuric  acid  has  been  volatilized, 
the  residue  is  treated  with  pure  ammonium  carbonate 
until  its  weight  becomes  constant.  It  is  now  dissolved 
in  water,  the  silica  removed,  and  the  sulphates  in  the 
filtrate  determined  as  barium  sulphate,  the  weight  of 
which  is  added  to  that  first  found.  If  the  hydrolysis, 
etc.,  can  be  carried  out  in  vessels  of  silver,1  the  above 
correction  is  unnecessary.  The  action  of  the  barium 
hydroxide  solution  is  promoted  by  the  previous 
addition  to  the  substance  of  a  few  drops  of  alcohol. a 
(d)  Magnesia  is  generally  employed  in  the  follow- 
ing manner:3  Ordinary  "ignited  magnesia,"  and  the 
basic  carbonate  (magnesia  alba)  are  both  unsuitable, 
as  they  contain  alkali  carbonates  which  are  difficult 
to  remove.  The  magnesia  is  prepared  from  the  sul- 
phate or  chloride,  which  must  be  free  from  iron ;  the 
solution  is  treated  with  alkali  hydroxide  in  quantity 
insufficient  to  cause  complete  precipitation ;  after 
thorough  washing  the  magnesia  is  retained  as  a  paste 
underwater.  The  acetyl  derivative  (i-i. 5  grams)  is 
intimately  mixed  with  the  magnesia  paste  (about  5 
grams)  and  a  little  water,  and  transferred,  together 
with  water  (100  cc),  to  a  flask  of  resistant  glass.  The 
mixture  is  boiled  in  a  reflux  apparatus  during  4-6 
hours,  although  usually  the  hydrolysis  is  completed 
in  2-3  hours.  The  liquid  is  concentrated  in  the  flask 
to  a  third  of  its  original  volume,  cooled,  filtered  by 
means  of  a  pump,  the  insoluble  portion  washed,  and 
the    filtrate     and    washings    treated    with  ammonium 

1  Lieben  and  Zeisel,  M.  4,  42;  7,  69. 

2  Barth  and  Goldschmiedt,  B.  12,  1237. 

■  H.  Schiff,  Ibid.  12,  1531.     Ann.  154,  n. 


DETERMINATION   OF   HYDROXYL.  1 3 

chloride,  ammonium  hydrate,  and  ammoniacal  sodium 
phosphate.  The  magnesium  ammonium  phosphate, 
after  standing  during  twelve  hours,  is  filtered,  dissolved 
in  dilute  hydrochloric  acid,  and  reprecipitated  by 
means  of  ammonium  hydrate ;  I  part  of  MgaPaO,  = 
0.774648  parts  of  C2H,0.  The  solubility  of  magnesia 
in  highly  dilute  solutions  of  magnesium  acetate  is  too 
small  to  require  a  correction.  Even  "insoluble" 
acetyl  derivatives  may  be  hydrolysed  by  magnesia, 
provided  that  they  are  in  a  finely  divided  state,  the 
boiling  being  prolonged  to  twelve  hours  if  necessary. 
The  magnesia  method  is  advantageous  in  cases  where 
the  use  of  alkali  causes  decomposition  and  the  pro- 
duction of  colored  substances  which  render  titration 
uncertain. 

(e)  If  hydrochloric  acid  (sulphuric  acid)  is  without 
action  on  the  hydroxyl  compound,  the  acetyl  deriva- 
tive is  heated  with  a  known  quantity  of  N/i  acid  in 
a  sealed  tube  or  pressure-flask  at  I20°-i50°,  and  the 
liberated  acetic  acid  titrated.1 

(f)  Hydrolysis  by  means  of  sulphuric  acid  is  espe- 
cially advantageous  when  the  original  substance  is 
insoluble  in  it.  The  acid  employed  should  be  free 
from  oxides  of  nitrogen  and  contain  75  parts  of  con- 
centrated acid  in  32  parts  of  water.  The  dilute  acid 
(10  cc)  is  mixed  in  a  flask  with  a  weighed  quantity  of 
the  acetyl  derivative  (about  1  gram),  which,  if  neces- 
sary, may  be  previously  moistened  with  three  or  four 
drops  of  alcohol ;  the  mixture  is  warmed  on'a  hot  but 
not  boiling  water-bath  during  a  half  hour,  diluted  with 

1  Schiitzenberger,  Ann.  de  Ch.  Ph.  84,  74.  Herzfeld,  B.  13, 
266.     Schmoeger,  Ibid.  25,  1453. 


14  RADICLES   IN   CARBON   COMPOUNDS. 

eight  volumes  of  water,  then  boiled  during  3-4  hours 
on  the  water-bath,  and  allowed  to  remain  during 
twenty-four  hours  at  the  ordinary  temperature.  The 
precipitated  hydroxyl  derivative  is  then  collected 
on  a  filter. x,a  Should  the  hydroxyl  derivative  not 
be  completely  insoluble  in  the  dilute  acid  a  blank 
experiment  must  be  made  and  the  correction  intro- 
duced.' 

(<£")  Hydriodic  acid  has  also  been  employed  for  the 
hydrolysis  of  acetyl  derivatives.8 

(B)  Additive  Method.4 

This  may  be  regarded  as  complementary  to  the 
method  described  under/".  In  cases  where  the  acetyl 
derivative  is  insoluble  in  cold  water,  and  the  acety- 
lation  proceeds  quantitatively,  the  yield  of  product 
from  a  given  weight  of  hydroxyl  compound  gives  a 
measure  of  the  number  of  acetyl  groups  introduced. 
This  method  has  recently  been  applied  to  the  investi- 
gation of  the  acetylation  products  of  tannic  acid.6 

(C)  Weighing  the  Potassium  Acetate." 

This  is  applicable  to  compounds  yielding  potas- 
sium salts  insoluble  in  absolute  alcohol.  The  acetyl 
derivative  (1-2  grams)  is  boiled  with  a  slight  ex- 
cess of  potassium  hydroxide  solution  until  it  is  com- 

1  Liebermann,  B.  17,  1682.     Herzig,  M.  6,  867-890. 

8  Ciamician  and  Silber,  B.  28,  1395. 

8  Ciamician,  Ibid.  27,  421,  1630. 

4  Goldschmiedt  and  Hemmelmayr,  M.  15,  321. 

6  H.  Schiff,  Ch.  Ztg.  20,  865.         •  Wislicenus,  Ann.  129,  175. 


DETERMINATION  OF  HYDROXYL.        1$ 

pletely  hydrolysed,  water  being  added  to  replace  that 
evaporated.  The  remaining  alkali  is  neutralized  with 
carbonic  anhydride,  the  liquid  evaporated  as  com- 
pletely as  possible  on  the  water-bath,  and  the  residue 
thoroughly  extracted  with  absolute  alcohol.  The 
alcoholic  solution  is  evaporated  to  dryness  and  the 
residue  again  extracted,  any  insoluble  matter  being  re- 
moved and  well  washed,  and  the  liquid  evaporated  in 
a  tared  vessel.  The  dried  potassium  acetate  remain- 
ing is  then  cautiously  fused,  allowed  to  cool  over  sul- 
phuric acid,  and  weighed. 

(D)  Distillation  Method. 

Fresenius1  first  suggested  that  the  acetic  acid 
from  acetates  could  be  liberated  with  phosphoric  acid 
and  determined  by  distillation,  with  or  without  the 
help  of  steam.  The  method  was  then  applied  by 
various  chemists  to  the  hydrolysis  of  acetyl  deriva- 
tives, but  since  they  replaced  the  phosphoric  acid  by 
sulphuric  acid  their  results  were  not  satisfactory.2 
Subsequently  the  use  of  phosphoric  acid  was  again 
proposed.3  The  acetyl  product  is  hydrolysed  by 
means  of  alkalis  or  barium  hydroxide,  acidified  at  the 
ordinary  temperature  with  phosphoric  acid,  filtered, 
and  well  washed ;  the  filtrate  and  washings  are  then 
distilled  until  the  distillate  is  completely  free  from 
acid,  fresh  water  being  introduced  into  the  retort  from 

1  Z.  anal.  Ch.  5,  315;  14,  172. 

*  Erdmann    and    Schulze,   Ann.   216,    232.     Buchka   and    Erk, 
18,  1142.     Schall,  Ibid.  22,  1561. 
3  Herzig,  M.  5,  go. 


1 6  RADICLES   IN   CARBON   COMPOUNDS. 

time  to  time  as  may  be  necessary.  The  distillation  is 
at  first  carried  out  over  a  flame  and  subsequently  from 
an  oil-bath,  the  temperature  being  allowed  to  rise  to 
I40°-I50°,  or  a  water-bath  may  be  employed,  in  which 
case  the  pressure  is  reduced.1  The  connections  must 
all  be  of  caoutchouc,  as  corks  would  absorb  acetic  acid, 
and  the  alkali  and  acid  employed  must  be  free  from 
nitrates  or  nitrites.  The  presence  of  chlorides  is  not 
hurtful,  as  these  do  not  liberate  hydrogen  chloride  in 
presence  of  the  phosphoric  acid,  which  is  one  advan- 
tage it  possesses  over  sulphuric  acid.3  The  distillate 
is  treated  with  baryta  water  in  excess,  and  concen- 
trated in  a  platinum  dish,  the  excess  of  barium  re- 
moved by  means  of  carbonic  anhydride,  and  the  fil- 
trate evaporated  to  dryness;  water  is  then  added,  the 
liquid  filtered,  the  insoluble  portion  well  washed,  and 
the  barium  in  the  filtrate  and  washings  determined  as 
sulphate,  I  gram  BaS04  =  0.5064  gram  CaH,0,  or 
0.5070  gram  C2H402. 

The  acetyl  groups  in  acetylated  gallic  acids  s  were 
determined  by  mixing  the  substance  (3-4  grams)  with 
pure  alcohol  (5  cc)  and  sodium  hydroxide  (2-3  grams) 
dissolved  in  water  (15  cc).  After  the  hydrolysis  was 
completed,  the  alcohol  was  dissipated,  the  residue 
acidified  with  phosphoric  acid,  the  acetic  acid  driven 
over  in  a  current  of  steam,  and  its  amount  determined 
by  titrating  the  distillate  with  sodium  hydrate  solu- 
tion, phenol'phthale'i'n  being  used  as  indicator.  One 
source  of   error  in  this  method   arises  from   carbonic 

1  H.  A.  Michael,  B.  27,  2686. 

2  R.  and  H.  Meyer,  Ibid.  28,  2967. 

»  P.  Sisley,  Bull.  Soc.  Chim.  III.  11,  562.     Z.  anal.  Ch.  34,466. 


DETERMINATION   OF  HYDROXYL.  1 7 

anhydride,  which  is  always  present  in  the  sodium 
hydrate,  and  is  often  produced  by  the  hydrolysis 
itself;  it  naturally  volatilizes  together  with  the  acetic 
acid.  The  difficulty  may  be  avoided  by  heating  the 
neutralized  liquid  to  boiling,  adding  a  very  small 
quantity  of  N/i  acid,  again  boiling,  and  then  neutral- 
izing, the  process  being  repeated  until  the  neutralized 
liquid  ceases  to  become  red  on  boiling;  this  shows 
that  all  the  carbonates  are  decomposed  and  no  loss  of 
acetic  acid  need  be  apprehended.  It  has  been  sug- 
gested '  that,  after  the  hydrolysis,  elimination  of  the 
alcohol,  ^and  acidification  by  means  of  phosphoric 
acid,  the  liquid  should  be  boiled  in  a  reflux  apparatus 
until  the  carbonic  anhydride  is  removed,  the  subse- 
quent operations  being  similar  to  those  above  described. 
Sources  of  error  in  this  method  are  described  on  p. 
26.a 

BENZOYL   DERIVATIVES, 
(i)    PREPARATION    OF    BENZOYL    DERIVATIVES. 

The  following  reagents  are  employed  for  the  intro- 
duction of  the  benzoyl  radicle  into  hydroxyl  com- 
pounds: 

Benzoyl  chloride  ; 

Benzoic  anhydride,  sodium  benzoate  ; 

p-Brombenzoyl  chloride,   p-Brombenzoic  anhydride  ; 

o-Brombenzoyl  chloride  ; 

m-Nitrobenzoyl  chloride  ; 

Phenylsulphonic  chloride. 


1  P.  Dobriner,  Z.  anal.  Ch.  34,  466,  foot-note. 

*  Cf.  Goldschmiedt  and  Hemmelmayr,  M.  14,  214;  15,  319. 


1 8  RADICLES  IN   CARBON   COMPOUNDS. 

(A)  Preparation  of  Benzoyl  Derivatives  by  Means 
of  Benzoyl  Chloride. 

(a)  The  ''acid"  method  consists  in  heating  the  sub- 
stance with  the  chloride  at  i8o°  during  several  hours 
in  a  reflux  apparatus;  it  is  not  advisable  to  employ  a 
sealed  tube  unless  there  is  assurance  that  the  hydro- 
chloric acid  will  not  cause  secondary  reactions  nor,  in 
the  case  of  nitrogenous  compounds,  combine  with 
them  to  form  hydrochlorides  which  would  then  cease 
to  react  f  when  this  may  occur  the  calculated  quantity 
of  chloride  is  employed,  and  the  heating  continued 
during  about  four  hours  at  ioo°-iio°. 

(b)  The  preceding  method  has  been  largely  super- 
seded by  the  use  of  the  chloride  in  dilute  aqueous  al- 
kaline solution.2  It  has  been  widely  applied,3  is  usually 
known  as  the  Schotten-Baumann  method,  and  seldom 
fails  to  give  good  results.  The  substance  is  well 
shaken  with  sodium  hydroxide  solution  (10$)  and 
benzoyl  chloride  in  excess  until  the  smell  of  the  latter 
is  no  longer  noticeable.4  If  the  benzoylation  is  to 
be  as  complete  as  possible  more  concentrated  alkali 
should  be  used,  say  fifty  parts  of  soda  (20$)  and  six 
parts  of  the  chloride  in  a  closed  flask.5  The  tempera- 
ture should  not  exceed  250,6  and  it  is  frequently  de- 
sirable to  add  the  alkali  and  chloride  alternately  little 
by  little,  whilst  in  some  cases  the  former  must  be  highly 

1  Danckwortt,  Arch.  Pharm.  228,  581. 

3  Lossen,  Ann.  161,   348;  175,  274,  319;  205,  282;  217,  16;  265, 
148,  foot-note. 

3  Baumann,  B.  19,  3218.  4  Baumann. 

5  Panormow,  B.  24,  R.  971.  6  v.  Pechmann,   Ibid.  25,  1045. 


DETERMINATION    OF   IIYDROXYL.  1 9 

dilute.1  It  has  also  been  found  to  be  advisable  to 
use  the  reagents  in  the  proportion  of  seven  molecules 
of  soda  and  five  of  the  chloride  to  each  hydro  xyl;' 
the  alkali  is  dissolved  in  water  (8-10  parts),  and  the 
shaking  and  gentle  cooling  continued  during  10-15 
minutes.  For  experiments  with  pyragallol  the  flask 
must  be  filled  with  coal-gas ;  in  the  case  of  similar 
substances  which  are  so  unstable  in  presence  of  caustic 
alkali,  sodium  carbonate,"  bicarbonate,  or  sodium 
acetate  may  be  used.4  The  precipitated  benzoyl  deriv- 
atives are  usually  white  and  semi-solid,  and  gradually 
harden  and  crystallize  by  prolonged  contact  with  water ; 
often  traces  of  benzoyl  chloride  or  benzoic  acid  are 
retained  with  great  tenacity.  For  the  purification  of 
the  benzoyl  derivative  of  dextrose  B  it  was  necessary  to 
dissolve  out  the  crude  product  with  ether;  this  was 
distilled  off,  and  the  residue  treated  with  alcohol, 
which  decomposed  the  last  portions  of  benzoyl  chlo- 
ride that  had  not  been  removed  by  prolonged  shaking 
of  the  ethereal  solution  with  concentrated  alkali.  The 
alcoholic  liquid  was  treated  with  soda  in  excess,  pre 
cipitated  with  water,  and  the  alcohol  and  ethylic  ben- 
zoate  removed  by  means  of  steam.  The  residue  was 
then  repeatedly  recrystallized  ;  at  first  from  alcohol, 
then  from  glacial  acetic  acid.  The  pure  compound  is 
insoluble  in  ether,  whilst  the  crude  preparation  readily 
dissolves.  Benzoic  acid  may  be  frequently  removed 
by  sublimation  in  vacuo,  or  by  extraction  with  boiling 

1  B.  31,  1598.  2  Skraup,  M.  10,  390. 

1  Lossen,  Ann.  265,  148.        4  Bamberger,  M.  &  J.,  II.,  p.  546. 
6  Skraup,  M.  10,  395. 


20  RADICLES    IN    CARBON    COMPOUNDS. 

carbon  bisulphide.1  Repeated  extraction  with  alkali 
is  usually  effective  for  the  purification  of  benzoyl  deriv- 
atives soluble  in  ether,  but  it  may  produce  partial  hy- 
drolysis. Commercial  benzoyl  chloride  often  contains 
chlorobenzoyl  chloride,"  and  since  the  chlorobenzoyl 
derivatives  are  less  soluble  than  the  benzoyl  derivatives 
themselves,  recrystallization  is  not  adequate  to  secure  a 
product  free  from  chlorine.  It  appears  also  that  pure 
benzoyl  chloride  may  yield  chloro-derivatives.3  Ben- 
zotrichloride  may  contain  benzal  chloride;  during  the 
conversion  of  the  former  into  benzoyl  chloride  by  the 
action  of  lead  oxide  or  zinc  oxide  the  latter  may  yield 
benzaldehyde,  the  presence  of  which  would  cause  com- 
plications.4 Lactones  often  yield  benzoyl  derivatives 
of  acids  which  are  soluble  in  alkali ;  they  are  separated 
by  ao  Jifying  and  removing  the  benzoic  acid  from  the 
precipitate  by  steam  distillation.6 

Schotten-Baumann's  method  has  also  been  applied 
to  the  preparation  of  acetyl  derivatives,  but  with 
comparatively  little  success  on  account  of  the  greater 
instability  of  acetyl  chloride.6 

(c)  Benzoyl  derivatives  may  also  be  prepared  in 
ethereal  or  benzene  solution,  with  the  help  of  dry 
alkali  carbonate,6  or  of  tertiary  bases  such  as  quinoline, 
pyridine,  or  dimethyl  aniline.7     (Cf.  p.  6.) 

(d)  Sodium  ethoxide8  may  also  be  employed  for  the 
decomposition  of  benzoyl  chloride,  and  it  was  only  in 

1  Barth  and  Schreder,  M.  3,  8oo. 

•  V.  Meyer,  B.  24,  4251.      Goldschmiedt,  M.  13,  55,  foot-note. 

3  B.  29,  2057.  4  Hoffmann  and  V.  Meyer,  Ibid.  25,  209. 

5  Ibid.  30,  127.  *  Ibid.  27,  3183. 

7  L.  Claisen,  Ibid.  31,  1023.  8  L.  Claisen. 


DETERMINATION  OF  HYDROXYL.        21 

this  manner  that  the  benzoyl  derivative  of  diacetyl- 
acetone  could  be  obtained.1  The  ketone  was  heated 
in  a  reflux  apparatus  during  six  hours,  with  two  molec- 
ular proportions  each  of  benzoyl  chloride  and  sodium 
ethoxide,  which  had  been  dried  at  2000 ;  after  cool- 
ing, the  sodium  chloride  and  benzene  were  removed, 
the  residue  dissolved  in  ether,  and  the  solution  shaken 
with  dilute  alkali. 

(e)  Pyridine  may  be  used  in  place  of  aqueous,  or 
alcoholic  alkali.2  The  product  is  triturated  with  dilute 
hydrochloric  acid  and  recrystallized  from  alcohol. 


(B)    Preparation   of  Benzoyl   Derivatives   from 
Benzoic   Anhydride. 

(a)  The  hydroxyl  compound  is  heated  with  benzoic 
anhydride,  in  an  open  vessel,  at  1500  during  1-2 
hours.3 

(b)  In  some  cases  the  use  of  benzoic  anhydride 
and  sodium  benzoate  produces  a  more  complete 
acylation  than  Schotten-Baumann's  method.4  As 
an  example  of  its  use,  scoparin  (2  grams),  benzoic 
anhydride  (10  grams),  and  dry  sodium  benzoate  (1 
gram)  were  heated  in  an  oil-bath  at  1900  during  six 
hours;  the  product  was  treated  at  the  ordinary  tem- 
perature overnight  with  aqueous  sodium  hydroxide 
(2$),  and  the  precipitated  hexabenzoyl  derivative 
purified  by  means  of  alcohol. 


1  Feist,  B.  28,  1824.  *  Deninger,  Ibid.  28,  1322. 

3  Liebermann,  Ann.   169,  237. 

4  Goldschmiedt  and  Hemmelmayr,  M.  15,  327. 


22  RADICLES   IN   CARBON   COMPOUNDS. 

Not  infrequently  the  addition  of  sodium  benzoate 
is  quite  unnecessary.1 


(C)     Preparation     of    Substituted     Benzoic    Acid 
Derivatives  and  of  Phenylsulphonic  Chloride. 

(a)  Parabromobenzoyl  chloride. * — Parabromoben- 
zoic  acid  is  intimately  mixed  with  the  equivalent 
quantity  of  phosphorus  pentachloride,  and  warmed 
until  the  evolution  of  hydrogen  -chloride  slackens. 
The  product  is  then  fractionated  under  reduced  pres- 
sure;  the  pure  compound  melts  at  420,  boils  at  1740 
(102  mm),  and  is  readily  soluble  in  benzene  and' 
light   petroleum. 

(b)  Parabromobenzoic  anhydride 3  is  prepared  by 
heating  sodium  parabromobenzoate  (3  parts)  with 
parabromobenzoyl  chloride  (2  parts)  at  2000  during 
an  hour.  It  melts  at  2120,  is  almost  insoluble  in  ether, 
carbon  bisulphide,  and  glacial  acetic  acid,  dissolves 
slightly  in  benzene,  and  is  purified  by  recrystallization 
from  chloroform. 

(c)  Orthobromobenzoyl  chloride*  is  prepared  in  a 
similar  manner  to  its  isomer.  It  is  a  liquid,  boiling 
at  24i°-243°,  and  may  be  distilled  under  the  ordinary 
pressure  without  decomposition. 

(d)  Metanitrobenzoyl  chloride b  is  formed  from  the 
nitrobenzoic  acid  by  gradually  and  intimately  mixing 
with   it   the    requisite   amount   of    phosphorus  penta- 

1  Arch.  Pharm.  235,  313.  2  B.  21,  2244. 

3  Schotten  and  Schlomann,  Ibid.  24,  3689. 
4  B.  21,  2244.     Schopf,  Ibid.  23,  3436. 
6  Claisen  and  Thompson,  Ibid.  12,  ic)43- 


DETERMINATION   OF   HYDROXYL.  23 

chloride;  the  phosphorus  oxychloride  is  removed  by 
distillation,  and  the  residue  fractionated  under  re- 
duced pressure.  It  melts  at  340  and  boils  at  1830- 
1840  (50-55  mm). 

(e)  Phenylsulphonic  chloride1  is  obtained  by  heating 
sodium  phenylsulphonate  with  phosphorus  penta- 
chloride  in  equivalent  proportions ;  when  the  action 
ceases  the  product  is  poured  into  water,  the  oily 
portion  removed,  washed  with  water,  dissolved  in 
ether,  and  the  solution  decolorized  by  treatment 
with  animal  charcoal.  The  compound  melts  at  140 
and  boils  at  1200  (10  mm). 


(D)  Acylation  by  Means  of  Substituted  Benzoic 
Acid  Derivatives  and  of  Phenylsulphonic 
Chlorides. 

(a)  Parabromobenzoyl  chloride,  or  parabromobenzoic 
anyhdride,  has  been  used  for  acylation,  the  number  of 
the  original  hydroxyl  groups,  being  determined  from 
the  bromine  content  of  the  product.3 

(b)  Ortliobromobenzoyl  chloride*  and  metanitroben- 
zoyl  chloride 4  are  also  well  adapted  for  the  determi- 
nation of  hydroxyl  groups. 

(c)  Phenylsulphonic  chloride0  has  been  employed  for 

1  Otto,  Z.  f.  Ch.  1866,  106. 

8  F.  Loring  Jackson  and  G.  W.  Rolfe,  Am.  Chem.  Journ.  9,  82; 
B.  20;  R.  524. 

3  Schotten,  Ibidf-21,  2250. 

4  Claisen   and   Thompson,    Ibid.  12,    1943.     Schotten,   Ibid.  21, 
2244. 

6  Hlnsberg,  B.  23,  2962.  Schotten  and  Schlomann,  Ibid.  24, 
3689. 


24  RADICLES   IN   CARBON   COMPOUNDS. 

the  same  purpose;  it  is  either  allowed  to  act  like  the 
benzoyl  chloride  in  the  Schotten-Baumann  method, 
or  it  is  warmed  with  the  hydroxyl  compound  (phenol) 
and  zinc  dust,  or  zinc  chloride.1 

Phenylsulphonic  derivatives  are  often  more  stable 
than  the  corresponding  benzoyl  compounds.4 

(2)   ANALYSIS    OF    BENZOYL    DERIVATIVES. 

(a)  The  exact  number  of  benzoyl  groups  in  many 
benzoyl  derivatives  is  shown  by  their  elementary 
analysis;  in  substitution  products  the  amount  of 
haloid,  nitrogen,  or  sulphur  is  determined. 

(b)  The  following  method  has  been  suggested  for 
the  direct  determination  of.  the  benzoic  acid:3  The 
substance  (about  0.5  gram)  is  hydrolysed  by  heating 
it  during  two  hours  at  ioo°,  in  a  sealed  tube,  with 
concentrated  hydrochloric  acid  (10  parts),  which  has 
been  saturated  with  benzoic  acid  at  the  ordinary 
temperature.  The  product  is  allowed  to  remain 
1-2  days  at  the  ordinary  temperature,  filtered  by 
means  of  the  pump,  and  the  precipitate  washed,  at 
first  with  more  of  the  hydrochloric  acid,  then  with 
a  saturated  aqueous  solution  of  benzoic  acid.  The 
purified  benzoic  acid  is  now  dissolved  in  N/10  so- 
dium hydroxide  solution  in  excess,  titrated  with 
excess  of  acid,  and  the  neutralization  effected  with 
the  needful  quantity  of  the  soda  solution.  The 
latter     is     standardized     against     pure    benzoic    acid, 

1  C.  Schiaparelli,  Gazz.  11,  65.  2  B.  30,  669. 

3  G.  Pum,  M.  12,  438. 


DETERMINATION   OF   HYDROXYL.  2$ 

phenolphthalein  being  employed  as  the  indicator. 
The  admixture  of  the  acid  and  water  during  the 
washing  of  the  benzoic  acid  always  causes  a  precipi- 
tation of  benzoic  acid,  so  that  the  results  obtained 
by  this  method  are  invariably  about  I  per  cent,  too 
high;  therefore,  this  amount  must  be  deducted  from 
the  percentage  of  acid  found,  or  the  exact  cor- 
rection ascertained  by  means  of  a  blank  experiment 
with  the  same  quantities  of  liquids  as  have  been  used 
in  the  main  one. 

(c)  A  method  of  more  general  application  consists 
in  separating  the  benzoic  acid  from  the  hydrolysed 
substance  by  means  of  a  current  of  steam,  and  ti- 
trating the  distillate;1  its  principle  is  therefore 
identical  with  the  determination  of  acetyl  groups, 
and  it  presupposes  that  the  compound  under  exam- 
ination is  completely  hydrolysed  by  alkalis,  and 
yields  no  acid  other  than  benzoic,  volatile  with 
steam.  The  substance  (about  0.5  gram)  is  mixed 
with  alcohol  (30-50  cc)  and  potassium  hydroxide 
in  excess,  and  heated  in  a  reflex  apparatus ;  when 
the  hydroylsis  is  completed  the  product  is  cooled, 
acidified  with  concentrated  phosphoric  acid  solution 
or  vitreous  phosphoric  acid,  and  distilled  in  a  cur- 
rent of  steam.  The  distillation  is  conducted  slowly 
at  first,  and  alcohol  added,  if  necessary,  by  means 
of  a  dropping  funnel,  the  object  being  to  secure 
the  gradual  deposition,  in  a  crystalline  state,  of  the 
hydrolysis  products  as  otherwise  resinous  substances 
might    surround    the    benzoic    acid   and   considerably 

1  R.  and  H.  Meyer,  B.  28,  2965. 


26  RADICLES   IN   CARBON    COMPOUNDS. 

hinder  its  volatilization.  When  the  distillate  meas- 
ures 1-1.5  liters,  the  following  150  cc  are  collected 
separately  and  tested  for  benzoic  acid  by  titration, 
and,  as  soon  as  it  is  no  longer  present,  the  distillation 
is  stopped.  The  combined  distillate  is  rendered  al- 
kaline with  a  known  quantity  of  N/10  sodium  hydrate 
solution,  standardized  against  pure  benzoic  acid,  and 
evaporated  in  a  platinum,  silver,  or  nickel  dish  to  a 
volume  of  100— 150  cc,  when  the  excess  of  alkali 
is  titrated  back,  the  liquid  being  boiled  to  expel 
carbonic  anhydride;  this  may  be  regarded  as  ac- 
complished when  boiling  during  ten  minutes  produces 
no  change  in  the  indicator,  which  is  aurin  or  rosolic 
acid.  In  order  to  guard  against  the  production  of 
sulphites  and  sulphates,  the  concentration  of  the 
alkaline  liquid  is  carried  out  by  means  of  a  spirit 
or  petroleum  lamp,  unless  a  special  gas  burner  is 
available. 

(d)  Benzoylmorphine  has  been  examined  by  direct 
titration.1  The  substance  was  dissolved  m  methylic 
alcohol,  mixed  with  a  little  water,  normal  sodium  hy- 
drate solution  (100  cc)  added,  and  boiled  in  a  reflux 
apparatus  until  a  portion  of  it  gave  no  turbidity 
with  water;  titration  with  normal  hydrochloric  acid, 
in  presence  of  phenolphthalein,  showed  that  the 
original  compound  was  the  monobenzoyl  derivative. 
The  same  method  was  successfully  applied  to  the 
analysis  of  dibenzoylpseudomorphine  and  tribenzoyl- 
meythlpseudomorphine. 

1  Vongerichten,  Ann.  294,  215.      Cf.  Knorr,  B.  30,  917-920. 


DETERMINATION   OF   HYDROXY!*  27 

ACYLATION    BY    MEANS    OF    OTHER   ACID 
RADICLES. 

Propionic  anhydride,  isobutyric  anhydride,  opianic 
acid,1  stearic  anhydride,2  and  phenylacetyl  chloride 
are  sometimes  used  for  acylation,  as  their  relatively 
high  boiling  points  facilitate  their  reaction  with  the 
hydroxyl  compound. 

(a)  Propionyl  derivatives  are  prepared  by  heating 
the  substance  with  propionic  anhydride,  in  a  stout, 
closed  bottle,  at  ioo°  during  two  hours;  an  open 
vessel  may  also  be  employed,  and  the  reaction  started 
by  the  addition  of  a  drop  of  concentrated  sulphuric 
acid.' 

{b)  Isobutyryl  derivatives  are  prepared  in  a  similar 
manner.  Isobutyryl  ostruthin  was  prepared  by  heat- 
ing ostruthin  (3  grams)  with  isobutyric  anhydride 
(10  grams)  in  a  sealed  tube  at  1500  during  3  hours. 
The  product  was  poured  into  water,  allowed  to  re- 
main until  it  became  crystalline,  washed  with  warm 
water  until  neutral,  pressed,  dried  by  means  of  filter 
paper,  and  recrystallized  from  alcohol.* 

(c)  Phenylacetyl  chloride  is  not  difficult  to  prepare,5 
and  is  used  e  like  benzoyl  chloride  in  Schotten-Bau- 
mann's  method,  the  substance  being  dissolved  in  di- 
lute aqueous  potassium  hydroxide  solution,  and  well 
shaken  with  excess  of  the  chloride. 

(d)  The  extent  to  which  phosphoric  acid  may  prove 
useful  remains  at  present  undetermined.7 

1  B.  31,  358.  3  Ann.  262,  5.  3  Arch.  Pharm.  228,  127. 

4  Jassoy,  Arch.  Pharm.  228,  551.  B  B.  20,  1389;  29,  1986. 

«  Hinsberg,  Ibid.  23,  2962.  T  Ibid.  30,  2368;  31,  1094. 


28  RADICLES   IN   CARBON   COMPOUNDS. 

II.   ALKYLATION  OF   HYDROXYL   GROUPS. 

The  hydroxyl  of  phenol  and  primary  alcohols  is 
capable  of  alkylation,  and  the  number  of  alkyl 
groups  introduced  may  be  determined  from  the 
resulting  ethers  by  Zeisel's  method  (cf.  p.  33). 
As  a  rule,  the  phenolic  ethers  are  not  hydrolysed 
by  alkalies  (cf.  p.  457),  hence  it  is  possible  to 
differentiate  between  the  hydroxyl  and  carboxyl 
of  the  hydroxy  acids.  It  has,  however,  been  shown 
that  the  use  of  potassium  hydroxide  and  alkyl 
iodides  may  lead  to  the  production  of  compounds 
with  the  alkyl  directly  linked  to  carbon,2  and  that, 
on  the  other  hand,  hydroxyl  in  the  ortho-position 
relative  to  carbonyl  oxygen  is  determinable  by  acy- 
lation,  but  not  by  alkylation.3 

Diazomethane  may  also  be  used  as  an  alkylating 
agent.4 

PREPARATION    OF   BENZYL   DERIVATIVES. 

Benzyl  ethers  of  phenols  are  prepared  by  heating 
the  latter  in  a  reflux  apparatus,  during  several  hours, 
with  the  calculated  quantities  of  sodium  ethoxide 
and  benzyl  chloride  in  alcoholic  solution,  the  pre- 
cipitated sodium  chloride  is  removed  by  filtration 
from    the    hot    liquid,6   and    the   composition   of    the 

1  B.  30,  2368;  31,  1094. 

s  Herzig  and  Zeisel,  M.  9,  217,  882;  10,  144,  735;  11,  291,  311, 
413;  14,  376. 

3  Graebe.  Herzig,  M.  6,  72,  Schunk  and  Marchlewsky,  Journ. 
Chem.  Soc.  65,  185.  Kostanecki,  B.  26,  71,  2901.  Perkin, 
Journ.  Chem.  Soc.  67,  995;  69,  801. 

4  v.  Pechmann,  B.  28,  856;   31,  64,  501,  Ch.  Ztg.  98,  142. 
6  Haller  and  Guyot,  C.  r.  116,  43. 


DETERMINATION   OF    HYDROXYL.  29 

ether  determined  by  elementary  analysis.  Benzyl 
iodide  may  also  be  employed  for  the  preparation 
of  these  compounds.1 

III.   PREPARATION     OF    CARBAMATES    BY 
MEANS  OF  CARBAMYL  CHLORIDE. 

PREPARATION    OF   CARBAMYL    CHLORIDE.3 

Ammonium  chloride  is  placed  in  a  distillation  flask 
attached  to  a  long  and  wide  condenser,  heated  at 
about  4000  in  an  air  bath,  and  treated  with  a  cur- 
rent of  carbonyl  chloride,  dried  by  means  of  sul- 
phuric acid.  The  carbamyl  chloride,  which  has  a 
highly  offensive  smell,  distils  over  and  condenses  to 
a  colorless  liquid,  or  to  long,  broad  needles  melting 
at  500.  It  volatilizes  at  6i°-62°,  and,  after  prolonged 
standing,  polymerizes  to  cyamelide,  for  which  reason 
it  should  be  employed  as  quickly  as  possible  after  its 
preparation.  In  contact  with  water  or  moist  air,  it 
is  hydrolysed  to  carbonic  anhydride  and  ammonium 
chloride. 

PREPARATION    OF    CARBAMATES. 

Carbamyl  chloride  reacts  with  hydroxyl  derivatives 
in  accordance  with  the  equation  : 

NH,  CO. CI  +  HO.R  ^  NH,.CO.OR  +  HC1, 
the    resulting   carbamates    readily    crystallize.3      It    is 

>*M.  &  J.  II.,  p.  125. 

2  Gattermann  &  G.  Schmidt,  B.  20,  858. 

5  Gattermann,  Ann.  244,  38. 


30  RADICLES   IN   CARBON   COMPOUNDS. 

usually  only  necessary  to  mix  the  substances  in 
equivalent  proportion  in  ethereal  solution  as  the  re- 
action generally  proceeds  quantitatively  at  the  ordinary 
temperature ;  in  the  case  of  some  polybasic  phenols 
gentle  warming  is  requisite.  The  amount  of  nitro- 
gen in  the  product  is  a  measure  of  the  number 
of  hydoxyl  groups  in  the  original  compound.  Great 
excess  of  the  chloride  should  not  be  used,  as  it 
may  lead  to  the  production  of  ethereal  allophanates, 
NH2.CO.NH.CO.OR. 

IV.    PREPARATION    OF    DIPHENYLCAR- 
BAMYL  CHLORIDE  (C.H.),  N.CO  CI. 

This  substance  has  been  found  especially  useful 
in  the  investigation  of  rhodinol  (geraniol).1  It  is 
prepared  by  dissolving  diphenylamine  (250  grams)  in 
chloroform  (700  cc),  adding  anhydrous  pyridine 
(120  cc),  and  passing  a  current  of  carbonyl 
chloride  (147  grams)  into  the  liquid,  which  is  main- 
tained at  o°.  After  remaining  during  5-6  hours, 
the  chloroform  is  distilled  off  on  the  water-bath, 
and  the  residue  crystallized  from  alcohol  (1.5  liters). 
The  yield  is  300  grams,  the  product,  after  recrys- 
tallization  from  alcohol  (1  liter),  is  pure,  and  melts 
at  84V 

1  Erdmann  and  Huth,  J.  pr.  53,  45. 

2  Ibid.  56,  7 


DETERMINATION   OF   HYDROXYL.  3 1 


V.   PREPARATION    OF   PHENYLCARBAMIC 
ACID  DERIVATIVES. 

PREPARATION    OF   PHENYLISOCYANATE.1 

Commercial  phenylurethane  (15  grams)  is  mixed 
with  phosphoric  anhydride  (30  grams)  in  a  small 
retort,  and  heated  by  means  of  a  luminous  flame, 
a  large  distillation  flask  being  employed  as  receiver; 
the  combined  distillate  from  a  number  of  such  prep- 
arations is  then  fractionated  once.  The  isocyanate 
boils  at  1690  (769  mm),3  and  the  yield  is  52-53  per 
cent.8 


ACTION     OF    PHENYLISOCYANATE     ON     HYDROXYL 
DERIVATIVES.4 

Ethereal  phenylcarbamates  are  formed  by  the  inter- 
action of  hydroxyl  compounds  and  phenylisocyanate 
in  equimolecular  proportion  in  accordance  with  the 
equation : 

R.HO  +  C6H6  N  :  CO  **  C6H6NH.CO.OR. 

The  reaction  often  proceeds  at  the  ordinary  tempera- 
ture, but  it  is  best  to  rapidly  boil  the  compounds,  mixed 
in  the  requisite  proportion,  by  means  of  a  previously 
heated  sand-bath,  and  complete  the  reaction  by 
shaking  and  gentle  warmth.6     Polybasic  phenols  are 

1  H.  Goldschmiedt,  B.  25,  2578,  foot-note. 

8  Hofmann,  B.  18,  764.  a  Zanoli,  Ibid.  25,  2578,  foot-note. 

4  Hofmann,  Ann.  74,  3;  B.  18,  518.     Snape,  Ibid.  18,  2428. 

5  Tessmer,  Ibid.  18,  969. 


32  RADICLES   IN   CARBON  COMPOUNDS. 

heated  in  a  sealed  tube  during  10-16  hours;1  if  the 
compound  eliminates  water  at  this  temperature  the 
phenylisocyanate  is  converted  by  it  into  carbonic  an- 
hydride and  carbanilide.2  The  duration  of  the  boil- 
ing in  an  open  vessel  should  be  shortened  as  much 
as  possible  to  reduce  the  production  of  diphenylcar- 
bamide.  When  cold  the  product  of  the  reaction 
is  treated  with  a  little  benzene  or  ether  to  dissolve  un- 
altered phenylisocyanate,  then,  after  the  removal  of 
the  benzene  or  ether,  washed  with  cold  water  and 
recrystallized  from  alcohol,  ethylic  acetate,  or  a 
mixture  of  ether  and  light  petroleum,  which  leaves 
the  sparingly  soluble  diphenylcarbamide  undissolved. 
The  presence  of  negative  groups  in  the  molecule  of 
the  hydroxyl  derivative  hinders  or  completely  pre- 
vents the  reaction ;  thus  trinitrophenol  gives  no  deriv- 
ative when  heated  at  1800  under  pressure.3 

An  attempt  has  been  made  to  determine  the 
presence  of  hydroxyl  groups  by  the  use  of  1  :2  -.4- 
chlordinitrobenzene.  * 

1  Snape,  B.  18,  2428. 

8  Tessmer,  Ibid.  18,  969.      Beckmann,  Ann.  292,  16. 

"Gumpert,  J.  pr.  31,  119;  32,  278. 

4  Vongerichten,  Ann.  294,  215. 


Chapter    IT. 

DETERMINATION  OF  METHOXYL.  CH36-,  ETHOXYL, 
CaH56-    AND   CARBOXYL,    CO.OH. 

I.  DETERMINATION  OF  METHOXYL,  CH36-. 

S.   ZEISEL'S   METHOD.1 

This  method,  which  is  distinguished  for  beauty 
and  reliability,  depends  on  the  conversion  of  the 
methyl  of  the  methoxy  group  into  methyl  iodide  by 
means  of  hydriodic  acid,  the  methyl  iodide  being 
then  decomposed  by  alcoholic  silver  nitrate  solution 
into  silver  iodide.  The  original  apparatus,  repre- 
sented in  Fig.  I,  consists  of  a  reversed  condenser 
K,  through  which  water  at  40°-50°  flows ;  at  the  lower 
end  a  flask  A  of  30-35  cc  capacity  is  attached  by 
means  of  a  cork ;  the  flask  has  a  side  tube  sealed  on 
through  which  a  current  of  carbonic  anhydride  may 
be  passed.  A  Geissler's  potash  bulb  is  connected  to 
the  upper  end  of  the  condenser,  also  by  means  of  a 
cork;  it  contains  0.25-0.5  gram  red  phosphorus 
suspended  in  water,**  and  is  maintained  at  a  tem- 
perature of  50°-6o°  by  the  water-bath  in  which  it 
is  placed.  Its  object  is  to  absorb  any  iodine  or 
hydriodic  acid  which  might   be  carried   over  by  the 

1  M.  6,  989  ;  7,  406. 

33 


34 


RADICLES   IN   CARBON   COMPOUNDS. 


methyl  iodide  vapor.      The  two  flasks  which  complete 
the  apparatus  have  a  capacity  of  80  cc  each,  the  first 


contains    50    cc    of    alcoholic  silver  nitrate    solution, 
the  second   25    cc;    they  are  connected   by  means  of 


METHOXYL,    ETIIOXYL,   AND   CARBOXYL.  35 

corks,  and  may  be  conveniently  replaced  by  two  dis- 
tillation flasks,  the  side  tube  of  the  first  being  bent 
downwards  at  a  right  angle  into  the  second.  A  modi- 
fied apparatus  has  been  described,  which  serves  as  a 
combined  condenser  and  washing  arrangement,1  and 
also  a  second  one,  which  has  in  addition  a  very  con- 
venient appliance  for  heating  and  supplying  the  water 
to  the  condenser.2  Modified  boiling  flasks,*  (Fig.  2), 
which    prevent   the    action    of    the    heated    hydriodic 

acid  on  the  cork,  have  been  designed.  If 
Jt*  the  substance  under  examination  is  not  vola- 
\sf  tile,    the    condenser    may    be    replaced    by   a 

vertical  tube  bent  back  in  a  U  shape.      The 

method  is  not  applicable  to  compounds  con- 
s  v  taining  sulphur,  and  the  hydriodic  acid  em- 
(  )  ployed  must  not  have  been  prepared  by 
F  ,  means  of  hydrogen  sulphide,  otherwise  it  is 

difficult  to  completely  free  it  from  volatile 
sulphur  compounds,  the  presence  of  which  would  be 
apt  to  cause  the  formation  of  mercaptanes  and  silver 
sulphide.  C.  A.  F.  Kahlbaum,  of  Berlin,  supplies 
"hydriodic  acid  for  methoxyl  determination,"  which 
is  prepared  by  means  of  phosphorus,  and  is  trust- 
worthy. Should  a  blank  experiment  show  that  the 
hydriodic  acid  produces  a  perceptible  precipitate  in 
the  silver  nitrate  solution,  it  must  be  purified  by  dis- 
tillation, the  first  and  last  quarters  of  the  distillate 
being  rejected;  it  should  have  a  sp.  gr.  —  1. 68-1. 72. 
Boiling    the    acid    with    a    reversed    condenser,    even 

1  Benedikt  and  Griissner,  Ch.  Ztg.  13,  872. 

1  L.   Ehmann,  Ibid.  14,  1767;   15,  221. 

3  Benedikt,  Ibid.  13,  872.     M.  Bamberger,  M.  15,  505. 


$6  RADICLES   IN   CARBON    COMPOUNDS. 

during  several  days,1  does  not  suffice  for  its  purifica- 
tion. The  silver  nitrate  solution  is  prepared  by  dis- 
solving the  fused  salt  (2  parts)  in  water  (5  parts)  and 
adding  absolute  alcohol  (45  parts!);  it  is  kept  in  the 
dark,  and  the  quantity  required  for  each  determina- 
tion filtered  into  the  absorption  flasks. 

I.    METHOD    FOR    NON- VOLATILE    SUBSTANCES. 

After  the  apparatus  is  put  together,  tested,  and 
found  to  be  air-tight,  the  silver  nitrate  solution  is 
introduced  into  the  absorption  flasks,  and  the  sub- 
stance (0.2-0.3  gram)>  together  with  the  hydriodic 
acid  (10  cc),  placed  in  the  distillation  flask;  unless 
Bamberger's  pattern  is  employed  this  should  also 
contain  a  few  pieces  of  porous  plate  to  regulate  the 
ebullition  ;  it  is  then  heated  to  boiling  in  a  glycerine- 
bath.  During  this  time  the  current  of  carbonic  anhy- 
dride is  passed  through  the  apparatus  at  the  rate  of 
three  bubbles  in  two  seconds.  The  gas  employed 
must  be  washed  with  water,  and  also  with  silver 
nitrate  solution,  to  remove  any  hydrogen  sulphide 
arising  from  impurities  in  the  marble.  The  warm 
water  must  also  be  supplied  to  the  condenser  and  the 
bath  containing  the  potash  bulbs.  Some  10-15  min- 
utes after  the  acid  begins  to  boil  the  silver  nitrate 
becomes  turbid  and  soon  a  white  double  compound  of 
silver  nitrate  and  silver  iodide  precipitates  in  the  first 
flask;  the  liquid  in  the  second  one  usually  remains 
clear,  but  sometimes  becomes  opalescent  if  the  current 
of  carbonic  anhydide   is  very  rapid  or  the  substance 

1  Benedikt. 


METHOXYL,    ETHOXYL,    AND    CARBOXYL.  37 

particularly  rich  in  methoxyl  groups,  these  conditions 
may  also  cause  the  precipitate  to  become  yellow.  The 
conclusion  o*f  the  experiment  is  readily  indicated  by  the 
complete  subsidence  of  the  precipitate,  which  becomes 
crystalline;  the  time  required  is  1-2  hours.  The  tubes 
and  flasks  with  the  silver  solution  are  disconnected, 
and  the  second  one  diluted  with  five  parts  of  water;  if 
no  precipitate  appears  after  remaining  several  minutes 
nothing  more  is  done  to  it,  otherwise  it  is  added  to 
the  contents  of  the  first  flask,  which  are  poured  into 
a  beaker,  any  precipitate  adhering  to  the  tubes  is 
removed  to  the  beaker  by  means  of  a  feather  and 
jet  of  water;  the  volume  is  now  made  up  to  about 
500  cc  with  water,  evaporated  to  one  half  on  the 
water-bath,  then  water  and  a  drop  of  nitric  acid 
added,  and  the  liquid  digested  until  the  silver  iodide 
is  completely  precipitated;  it  is  then  filtered  and 
weighed  in  the  usual  manner.  The  precipitate  adher- 
ing to  the  tubes  is  usually  dark-colored,  possibly  from 
the  presence  of  a  trace  of  phosphorus,  "but  this  does 
not  affect  the  accuracy  of  the  determination.  100 
parts  of  silver  iodide  =  13.20  parts  of  CH30  =  6.38 
parts  of  CHS.  The  method  is  applicable  to  com- 
pounds containing  chlorine,  bromine,1  or  nitro-groups, 
but  not  to  sulphur  compounds.2  In  the  case  of 
nitro-derivatives,  or  other  compounds  which  readily 
liberate  iodine  from  hydriodic  acid,  it  is  desirable 
to  place  a  little  red  phosphorus  in  the  boiling-flask. 
The  potash  bulbs  require  refilling  after  four  or  five 
determinations.       Hydriodic   acid    causes    many  sub- 

1  G.   Pum,  M.  14,  498. 
5  Zeisel.  Ibid.  7,  409.      Benedikt  and  Bamberger,  Ibid.  12,  1. 


38  RADICLES   IN   CARBON   COMPOUNDS. 

stances  to  become  resinous,  and  the  resin  may  protect 
a  portion  of  the  methoxy  compound  from  the  action  of 
the  acid.  This  difficulty  may  be  overcome  by  adding 
to  the  acid  acetic  anhydride  (6-8  volumes  per  cent),  as 
was  shown  in  the  case  of  methyl  and  acetylethyl- 
quercetin,  rhamnetin,  and  triethoxyphloroglucinol.1 
The  method  is  also  well  adapted  for  the  determination 
of  alcohol  of  crystallization.2 

2.     MODIFICATIONS    OF     THE    METHOD    FOR    ITS    USE 
WITH    VOLATILE    COMPOUNDS. 

Volatile  substances  may  usually  be  treated  in  the 
manner  described  above  if,  at  the  commencement  of 
the  experiment,  a  slow  stream  of  carbonic  anhydride  is 
employed  and  cold  water  run  through  the  condenser. 
The  following  special  modifications  for  particularly 
volatile  compounds  have  been  suggested.8  The  sub- 
stance (o.i -0.3  gram)  is  sealed  into  a  small  bulb  of 
thin  glass,  which  is  sealed  up  in  a  larger  tube  together 
with  hydriodic  acid  (10  cc,  sp.  gr.  =  1.7)  and  a 
piece  of  heavy  glass  about  2  cm  in  length  with  a 
sharp  corner.  The  heavy  glass  is  to  assist  in  break- 
ing the  bulb  with  the  substance  before  the  heating, 
but  is  unnecessary  if  the  latter  is  enclosed  in  test- 
tube  glass  with  a  long  capillary.  The  larger  tube 
is  30—35  cm  long  and  1.2—  1. 5  cm  inner  diameter; 
both  ends  are  drawn  out,  the  one  to  fit  into  a  tube 
10    cm  long  and    1-2    cm  inner  diameter,   which    is 

1  Herzig,  M.  9,  544.     Cf.  Pomeranz,  Ibid.  12,  383. 
8  J.  Herzig  and  H.  Meyer,  Ibid.  17,  437. 
8  Zeisel,  Ibid.  7,  406. 


METHOXYL,    ETHOXYL,   AND   CARBOXYL.  39 

sealed  to  a  wider  tube,  the  other  so  that  a  piece  of 
stout  rubber  tube  will  fit  over  it  quite  tightly.  The 
drawn-out  ends  must  be  strong  enough  to  resist  the 
pressure  during  the  heating,  and  sufficiently  thin  to  be 
readily  broken  after  being  scratched  with  a  file.  The 
substance  and  hydriodic  acid  are  heated  at  1300  during 
two  hours,  then,  when  cold,  one  point  of  the  tube  is 
fitted  into  the  narrow  one  mentioned  above,  the  wide 
portion  of  which  passes  through  a  triply  bored  cork 
into  a  wide-mouthed  flask.  Into  the  second  opening 
of  the  cork  the  condenser  fits,  whilst  the  third  con- 
tains a  piece  of  stout  glass  rod  bent  to  a  Z  form ;  by 
turning  this  the  drawn-out  end  of  the  heating-tube  is 
broken.  The  contents  are  transferred  to  the  flask 
partly  by  shaking,  partly  by  gently  warming;  the 
upper  capillary  is  covered  with  a  piece  of  rubber,  the 
end  broken,  and  a  current  of  carbonic  anhydride 
immediately  passed  through  the  apparatus.  The 
determination  then  proceeds  in  the  manner  already 
described. 

3.    MODIFICATION    OF    ZEISEL'S    METHOD.1 

Instead  of  red  phosphorus  and  water  the  potash  bulbs 
contain  a  solution  consisting  of  arsenious  anhydride 
(1  part),  potassium  carbonate  (1  part),  and  water  (10 
parts).  The  bulbs  must  be  refilled  for  each  deter- 
mination to  prevent  the  apparatus  becoming  choked 
with  precipitated  anhydride,  but  this  is  compensated 
for  by  the  fact  that  not  the  slightest  reduction  (black- 

1  T-  Gregor,  M.  19,  116. 


40  RADICLES   IN   CARBON   COMPOUNDS. 

erring)  of  the  silver  nitrate  solution  takes  place.  The 
N/io  silver  nitrate  solution  is  made  by  dissolving  the 
nitrate  (17  grams)  in  water  (30  cc)  and  diluting  to  a 
liter  with  commercial  absolute  alcohol,  its  titer  being 
determined  by  means  of  N/10  potassium  thiocyanate 
solution.  For  the  alkyloxyl  determination  the  silver 
solution  (75  cc)  is  acidified  with  a  few  drops  of  nitric 
acid,  free  from  nitrous  acid,  and  divided  between  the 
two  absorption  flasks.  At  the  conclusion  of  the  ex- 
periment the  silver  solution  with  the  precipitate  is  di- 
luted with  water  to  250  cc,  cautiously  shaken,  filtered 
by  means  of  a  dry  ribbed  filter  into  a  dry  flask,  and 
50  cc  or  100  cc  of  the  clear  filtrate  acidified  with 
nitric  acid,  free  from  nitrous  acid,  treated  with  ferric 
sulphate  solution,  and  titrated  in  the  ordinary  manner.1 

METHOD    FOR     THE     DIFFERENTIATION     OF 
METHOXYL    AND    ETHOXYL. 

Zeisel's  method  does  not  distinguish  between  meth- 
oxyl  and  ethoxyl ;  should  this  be  necessary,  the  alkyl 
iodide  must  be  prepared  in  quantity  sufficient  for  its 
identification,  or,  if  possible,  Lieben's  iodoform  test 
must  be  applied.  For  the  differentiation  of  the  alkyls 
the  investigation  of  the  action  of  phenyl  isocyanate 
on  the  alkyloxy  derivatives  has  been  suggested.* 
The  compound  is  heated  with  phenyl  isocyanate,  in 
equimolecular  proportion,  at  1500  during  several 
hours  in  a  sealed  tube.  The  product  is  steam-dis- 
tilled   and  the   volatile  portion  purified  by  recrystal- 

1  Volhard,  J.  pr.  9,  217.    Ann.  190,  1.    Z.  anal.  13,  171;  17,482. 

2  Beckmann,  Ann.  292,  9,  13. 


METIIOXYL,    ETIIOXYL,    AND    CARBOXYL.  41 

lization  from  a  mixture  of  ether  and  light  petroleum; 
methylphenylurethane  melts  at  47°,  ethylphenyl- 
urethane  at  500,  and  they  can  be  further  distinguished 
by  analysis. 

DETERMINATION    OF     ETHOXYL    (C2H56-). 

The  determination  of  ethoxyl '  is  carried  out  exactly 
in  the  manner  described  in  the  preceding  section  for 
methoxyl  except  that  the  water  in  the  condenser  and 
in  the  bath  surrounding  the  potash  bulbs  should  be 
heated  at  about  8o°.  100  parts  of  silver  iodide 
=  19.21  parts  C2H&0  ==  12.34  parts  CaH6. 


DETERMINATION    OF   CARBOXYL  (CH.OH). 

The  following  methods  are  employed  for  the  de- 
termination of  the  basicity  of  organic  acids: 

(A)  Analysis  of  metallic  salts  of  the  acid. 

(B)  Titration. 

(C)  Etherification. 

(D)  Determination  of  the  electrolytic  conductivity 
of  the  sodium  salts. 

(E)  Indirect  methods: 

(1)  Carbonate  method. 

(2)  Ammonia  method. 

(3)  Hydrogen  sulphide  method. 

(4)  Iodine  method. 

It  is  easy  to  decide  which  of  these  methods  is  the 
most  suitable  for  any  special  case,  but  the  qualitative 
differentiation    between    carboxyl     and    phenolic    hy- 

1  Zeisel,  M.  7,  406. 


42  RADICLES    IN   CARBON    COMPOUNDS. 

droxyl  frequently  presents  difficulties  that  can  only  be 
overcome  with  certainty  by  the  preparation  of  the 
amide  and  its  conversion  into  the  nitrile. 

(A)    Determination    of    Carboxyl    by   Analysis    of 
Metallic  Salts  of  the  Acid. 

In  many  cases  the  number  of  carboxyl  groups  in  an 
organic  compound  may  be  determined  by  the  analysis 
of  its  neutral  salts;  of  these  the  silver  salts  are  usually 
the  most  appropriate,  as  they  are  generally  formed 
directly  without  admixture  of  hydrogen  salts  and  are 
almost  always  anhydrous.  Exceptions  to  this  rule 
are,  however,  encountered ;  thus  the  silver  salts  of 
cantharidinic  acid,1  camphoglycuronic  acid,2  and  meta- 
quinaldinic  acid  3  crystallize  with  one,  three  and  four 
molecules  of  water  respectively,  and  hydrogen  silver 
salts,4  though  not  of  frequent  occurrence,  are  known. 
Aromatic  hydroxymonocarboxylic  acids  containing 
two  nitro-groups  often  give  salts  containing  two  atoms 
of  silver.  As  examples  may  be  mentioned  3  :5-dinitro- 
hydrocumaric,  1  13  :  5-dinitroparahydroxy benzoic  and 
2  :  6-dinitro-5  -hydroxy- 3 -4-dimethylbenzoic  acids.5 
Many  silver  salts  are  very  sensitive  to  light  or  air, 
and  some,  like  silver  oxalate,  are  explosive ;  for  the 
analysis  of  such  the  compound  is  dissolved  or  sus- 
pended in  water  or  acid,  and  treated  with  hydrogen 

1  Homolka,  B.  19,  1083. 

8  Schmiedeberg  and  Meyer,  Z.  physiol.  Chem.  3,  433. 

3  Eckhardt,  B.  22,  276. 

4  A  list  of  them  is  given  in  Lassar-Cohn   "  Manual  of  Organic 
Chemistry,"  translated  by  Alex.  Smith,  p.  345. 

5  W.  H.  Perkin,  Jun.,  Journ.  Chem.  Soc.  (1899),  75,  176. 


METHOXYL,    ETHOXYL,   AND   CARBOXYL.  43 

sulphide  or  hydrochloric  acid.  Silver  salts  which  do 
not  explode  when  heated  are  usually  analyzed  by  igni- 
tion in  a  porcelain  crucible ;  if  the  residual  silver  con- 
tains carbon  it  is  dissolved  in  nitric  acid,  the  solution 
diluted  and  filtered,  and  the  silver  precipitated  by 
means  of  hydrochloric  acid. 

Pyridine  and  quinoline  derivatives  and  amino-acids 
in  particular  often  give  characteristic  copper  and  nickel 
salts,  whilst,  in  the  aliphatic  series,  the  zinc  salts  may 
often  be  usefully  employed.  Sodium,  potassium,  cal- 
cium, barium,  magnesium,  and,  less  frequently,  leaa 
salts  are  also  sometimes  used  for  the  determination  of 
basicity,  but,  as  many  acids  do  not  yield  well-defined 
neutral  salts,  and  groups  other  than  carboxyl  can  ex- 
change hydrogen  for  metal,  the  method  has  not  a 
very  wide  application. 

(B)  Titration  of  Acids. 

The  basicity  of  a  carboxyl  derivative  may  often  be 
determined  by  titration  if  the  molecular  weight  of  the 
compound  is  known;  N/10  sodium  hydroxide,  potas- 
sium hydroxide,  or  barium  hydroxide  may  be  used 
for  the  titration  in  aqueous  solution,  or,  in  the  case  of 
the  first  two,  in  alcoholic  solution.  N/2  ammonium 
hydroxide  has  also  been  employed.1  The  acids  used 
are  generally  hydrochloric  or  sulphuric,  but  the  latter 
is  unsuited  for  work  with  alcoholic  solutions,  as  the 
precipitation  of  insoluble  sulphates  prevents  a  correct 
observation  of  the  end  reaction.  The  liquid,  alcohol, 
ether,  etc.,  in  which  the  compound  under  examination 

1  Haitinger  and  Lieben,  M.  6,  292. 


44  RADICLES   IN   CARBON   COMPOUNDS. 

is  dissolved  must  either  be  free  from  acids  or  must  be 
previously  accurately  neutralized  by  means  of  N/io 
alkali.  Phenolphthaleln,  methyl  orange,  rosolic  acid, 
curcumin,  or  litmus,  are  usually  employed  as  indi- 
cators, the  first  two  more  frequently  than  the  others. 
If  the  liquid  is  dark  colored  the  use  of  "  alkali  blue" 
is  often  convenient,  and  attention  must  always  be 
paid  to  the  possible  presence  of  carbonic  anhydride. 
A  somewhat  curious  and  interesting  attempt  has  been 
made  to  determine  the  neutrality  by  taste.1 

(C)     Etherification. 

In  very  many  cases  carboxylic  and  phenolic  hydrogen 
may  be  differentiated  by  the  etherification  of  the  com- 
pound with  alcohol  and  hydrogen  chloride.  It  has, 
however,    been    shown 3    that    acids    with    the    group 

C.COOH 

/\  (t  and  t'  =  tertiary  carbon   atom)   do  not 

c   c 

t       t 

yield  esters  with  alcohol  and  hydrogen  chloride  if 
both  the  carbon  atoms  marked  t  are  linked  to  CI,  P  , 
I,  or  N02,  whilst  the  groups  of  smaller  mass  F,  CH3, 
OH  in  the  same  positions  greatly  retard,  but  do  not 
entirely  prevent,  etherification.  On  the  other  hand, 
certain  phenols  such  as  phloroglucinol,"  which  gives  a 
diether,  hydroxyanthracene  (anthrol  and  a-  and  /3- 
naphthol  * )  yield  ethers  when  treated  with  hydrogen 

1  T.  W.  Richards,  Am.  Chem.  Journ.,  20,  125. 

2  V.  Meyer  and  others.      Many  papers  appeared  on  the  subject 
beginning  B.  27,  510,  and  ending  29,  2569. 

*  Ibid.  17,  2106;  21,  603. 

4  Liebermann  and  Hagen,  Ibid.  15,  1427. 


45 

chloride  and  alcohol.  The  etherification  is  most  con- 
veniently carried  out  by  boiling  the  substance  during 
3-5  hours  in  a  reflux  apparatus  with  a  large  excess  of 
absolute  alcohol  containing  3-5  per  cent  of  hydrogen 
chloride  or  sulphuric  acid.1  Occasionally  alcohol  of 
95  per  cent  may  be  employed  if  more  sulphuric  acid 
is  used.2  Some  substances  form  additive  compounds 
with  alcohol  and  hydrogen  chloride.3  This,  as  also  the 
contamination  of  the  ester  by  traces  of  chlorine 
derivatives,  which  can  only  be  removed  with  difficulty, 
may  lead  to  confusion. 

The  esters  obtained  by  acid  or  alkaline  etherifica- 
tion are,  in  general,  distinguished  from  the  phenolic 
ethers  by  the  ease  with  which  aqueous  or  alcoholic 
alkalis  hydrolyse  them,  but  exceptions  are  known 
since  trinitromethoxybenzene  (methoxy  picrate)  when 
boiled  with  concentrated  potassium  hydroxide  yields 
methyl  alcohol  and  potassium  picrate,4  and  methoxy- 
anthracene  (methyl  anthranol)  is  also  decomposed  by 
boiling  with  alcoholic  potash.6  The  composition  of 
the  esters  is  determined  by  elementary  analysis,  and 
the  alkyloxy  groups  by  the  methods  described  in  the 
earlier  portion  of  this  chapter. 

1  E.  Fischer  and  A.  Speier,  B.  28,  3252. 

a  Bishop  Tingle  and  A.  Tingle,  Am.  Chem.  Journ.  21,  243. 

•  Freund,  B.  32,  171. 

4  Ann.  174,  259. 

5  Liebermann  and  Hagen,  B.  15,  1427. 


46  RADICLES   IN   CARBON   COMPOUNDS. 


(D).  Determination  of  the  Basicity  of  Acids  by 
means  of  the  Electrolytic  Conductivity  of 
the  Sodium  Salts. 

It  has  been  shown  that  the  degree  of  electrolytic 
conductivity  of  the  sodium  salt  is  a  certain  indication 
of  the  basicity  of  the  corresponding  acid.1  The  method 
is  of  very  general  application,  since  insoluble  acids 
usually  yield  sodium  salts  which  dissolve  in  water, 
but  it  fails  in  the  case  of  acids  which  are  so  feeble 
that  their  sodium  salts  are  hydrolysed  by  water 
sufficiently  to  impart  an  alkaline  reaction  to  the  solu- 
tion. The  following  apparatus  is  required  for  the 
determination  : 

(i)  A  small  induction  coil  (J,  Fig.  5),  such  as  is  em- 
ployed for  medicinal  purposes,  and  which  requires  only 
one  or  two  cells  for  prolonged  use.  The  spring  of  the 
interrupter  must  vibrate  rapidly  so  as  to  produce  a 
high  pitched  sound  in  the  telephone,  as  this  is  more 
easily  heard  than  a  deeper  tone. 

(2)  A  bridge  consisting  of  a  scale  100  cm  in  length 
divided  into  millimeters;  along  it  stretches  a  wire 
provided  with  a  sliding  contact.  The  wire  is  of 
platinum,  German  silver,  platinoid,  or  manganin,  of 
which  the  last  is  the  best  on  account  of  its  low  tem- 
perature coefficient.      The  wire  must  be  calibrated.2 

(3)  A    rheostat    for    adjusting    the    resistance    (W, 

Fig-  5)- 

1  Ostwald,  Z.  2,  901;   1,  74.     Valden,  Ibid.  1,  529;  2,  49. 

8  Strouhal  and  Barus,  Wied.  Ann.  10,  326.  The  method  is  also 
described  by  Jones,  **  Freezing-point,  Boiling-point,  and  Con- 
ductivity Methods,"  Chem.  Pub.  Co.,  1897. 


METHOXVL,    ETHOXYL,    AND    CARBOXYL 


47 


x^r 


Fig.  3- 


(4)  A  resistance  cell  for  the  electrolyte  (E,  Fig.  5). 
Kohlrausch's  form  (Fig.  3)  is  used  for  low  resist- 
ances whilst  that  of 
Arrhenius  (Fig.  4)  is 
employed  for  dilute 
solution  where  the  re- 
sistance is  high.  The 
electrodes  must  be 
platinised  by  filling 
the  vessel  with  a 
dilute  solution  of  hy- 
droplatinochloric  acid  Fig.  4. 

and  passing  a  current  of  4-5  volts.  The  direction  of  the 
current  is  changed  occasionally  and  the  electrolysis 
continued  until  both  electrodes  are  completely  covered 
with  platinum  black,  which  only  requires  a  short 
time  ;  the  platinum  chloride  in  the  cell  is  now  replaced 
by  sodium  hydroxide  solution,  the  electrolysis  con- 
tinued for  a  few  moments,  the  electrodes  then 
thoroughly  and  carefully  washed  with  hydrochloric 
acid,  and  finally  with  water;  the  sodium  hydroxide 
removes  all  chlorine  which  is  otherwise  very  obsti- 
nately retained  by  the  platinum.  The  use  of  Lummer 
and  Kurlbaum's  solution  for  platinizing  is  highly 
recommended,  as  the  tone  minima  are  much  more 
distinct.1  The  solution  consists  of  platinum  chloride 
(1  part),  lead  acetate  (0.008  part),  and  water  (30 
parts);  it  is  electrolysed  with  a  current  density  of  O.03 
amperes  per  sq.  cm.,  the  direction  of  the  current 
being  frequently    changed   and   continued   until    each 


Kohlrausch,  Wied.  Ann.  1897,  p.  315;  E.  Cohen,  Z.  25,  1611. 


48  RADICLES   IN    CARBON   COMPOUNDS. 

electrode  has  been  the  cathode  during  at  least  fifteen 
minutes. 

(5)  A  telephone.  Ostwald  states  that  the  most  sen- 
sitive ones  are  made  by  Ericsson  of  Stockholm,  but 
for  ordinary  purposes  a  Bell  instrument  is  sufficiently 
good.  In  using  it  the  unoccupied  ear  may  be  closed 
with  cotton  to  exclude  external  sounds. 

(6)  A  zvater-batJi  with  stirrer  and  thermometer,  or  a 
thermostat.* 

The  apparatus  is  arranged  in  the  form  of  Kirch- 
hoff's  modification  of  the  Wheatstone  bridge  (Fig.  5), 
the  connections  being  made  with  stout  copper  wire. 
The  induction   coil  is  enclosed  in  a  sound  tight  case, 

or  is  placed  in  another 
room.  If  determinations 
of  solutions  of  a  substance 
at  different  concentrations 
are  to  be  made  the  solu- 
tion is  most  conveniently 
prepared  in  the  resistance 
cell  itself,  portions  are  then  withdrawn  by  means  of  an 
accurately  calibrated  pipette,  and  the  desired  volume 
of  water  added  which  has  previously  been  brought  to 
the  necessary  temperature  in  the  thermostat.  As  a 
rule  the  telephone  does  not  give  an  absolutely  sharp 
minimum  at  any  given  point,  but  it  is  easy  to  find 
two  limits  beyond  either  of  which  the  tone  rises; 
these  are  usually  separated  by  an  interval  of  0.5—2 
mm,    and   the   required   position   is  taken   as   midway 


1  Ostwald,  Z.  2,  564,  where  also  a  good  description  of  the  other 
parts  of  the  apparatus  is  given. 


METHOXYL,    ETHOXYL,   AND    CAKBOXYL.  49 

between  them.  A  little  experience  enables  the  con- 
ductivity to  be  determined  with  an  accuracy  of  o.  1 
per  cent.  If  the  tone  minimum  becomes  indistinct 
the  electrodes  must  be  replatinised.  The  conductivity 
is  calculated  from  the  measurements  by  means  of  the 

formula  p.  =  k  .  — '— ,  where 
w .  b 

jli=  the  molecular  conductivity; 

v  ==  the  volume  of  the  solution  in  liters  which  con- 
tains a  gram  molecule  of  the  electrolyte ; 

w  =  the  adjusting  resistance; 

a  =  the  length  of  wire  to  the  left  of  the  sliding  con- 
tact (Fig.  5); 

b  ss  that  to  the  right  of  the  contact  (Fig.  5) 

k  =  the  resistance  of  the  cell. 

The  value  of  k  is  determined  by  measuring  the  con- 
ductivity of  N/50  solution  of  potassium  chloride,  for 
which  Kohlrausch  found  the  values: 

fx  =  112. 2  at  180. 
/i  —  129.7  at  250. 

Other  solutions   may   also   be   used.1      The  value  - 

a 

for  a  wire  1000  mm  in  length  has  been  calculated  by 
Obach  and  an  abbreviated  table  of  the  results  is  given 
in  the  appendix.  The  conductivity  of  the  water  em- 
ployed, which  should  be  as  highly  purified  from  dis- 
solved substances  as  possible,  is  determined  in  the 
same  manner  as  that  of   the   solution,   the  value  for 

1  Wiedemann  and  Ebert,  Physik.  Praktikum,  p.  389. 


$0  RADICLES   IN   CARBON   COMPOUNDS. 

each  liter  (v)  is  calculated  according  to  the  formula, 
and  subtracted  from  the  uncorrected  value  of  //.  For 
basicity  determinations  the  conductivity  is  usually 
determined  at  concentrations  of  one  gram  molecule  in 
32  and  1024  liters  respectively.  The  mean  difference 
A  between  these  values  is  as  follows: 


Monobasic  acids 
Dibasic  " 

Tribasic  " 

Tetrabasic      " 
Pentabasic     ' ' 


.  A  =  10.4  =  1   x  10.4 
.  A  =   19.0  =  2  x     9-5 

.  A  =  30.2  =  3  x  10. 1 

.  A  =  41. 1  =:4x  10.3 

.  A  =  50.1  =  5  X  10 


A  method  has  been  described  '  for  determining  the 
basicity  of  acids  based  on  the  alterations  which  they 
exhibit  in  electrolytic  conductivity  on  the  addition  of 
alkali. 

Instead  of  the  telephone  and  induction  coil,  a  double 
commutator  and  a  galvanometer  may  be  used  to 
determine  the  electrolytic  conductivity,  the  commutat- 
ing  apparatus,  termed  a  secohmmeter,  is  so  arranged 
that  one  commutator  is  included  in  the  battery  circuit 
and  the  other  in  that  of  the  galvanometer;  on  rotating 
the  current  is  reversed  in  the  liquid  so  frequently 
that  polarization  is  annulled  whilst  the  galvanometer  is 
commuted." 

D.  Be-thelot,  C.  r.  112,  287. 

Cahart  and  Patterson,  "  Electrical  Measurements,"  p.  109. 


METHOXYL,    ETHOXYL,    AND    CARliOXYL.  5 1 


(E)  Indirect  Methods  for  the  Determination  of 
the  Basicity  of  Acids. 

These  methods  may  be  divided  into  four  classes 
according  to  the  nature  of  the  substance  liberated  by 
the  acid : 

(i)   Carbonate  method. 

(2)  Ammonia  method. 

(3)  Hydrogen  sulphide  method. 

(4)  Iodine-oxygen  method. 

(1)  Carbonate  Method. — The  substance  (0.5— 1  gram) 
is  dissolved  in  water  in  a  flask  closed  by  a  rubber 
stopper  with  three  holes.  In  one  hole  a  condensing 
tube  is  fitted,  which,  at  the  lower  end,  is  flush  with 
the  stopper  whilst  the  upper  end  is  connected  with  an 
absorption  apparatus  consisting  of  two  calcium  chloride 
tubes  and  potash  bulbs.  Through  the  second  hole  a 
tube  passes  to  the  bottom  of  the  flask,  the  end  being 
drawn  out  and  bent  upwards;  by  means  of  this  tube  a 
current  of  air,  free  from  carbonic  anhydride,  is  passed. 
The  third  hole  of  the  flask  is  closed  with  a  small 
dropping  funnel,  the  end  of  which  is  also  drawn  out 
and  bent  upwards  and  dips  below  the  liquid  in  the 
flask.  The  solution  of  the  acid  is  gently  boiled,  and 
barium  carbonate,  in  the  form  of  a  thin  paste,  is  added 
in  small  quantities  by  means  of  the  funnel.  When  the 
operation  is  completed  the  apparatus  is  allowed  to  cool 
in  a  current  of  purified  air,  again  boiled,  cooled,  and 
the   absorption   bulbs  weighed.1     A   similar   method, 

1  Goldschmiedt  and  Hemmelmayr,  M.  14,  210. 


52  RADICLES   IN   CARBON   COMPOUNDS. 

based  on  the  decomposition  of  sodium   hydrogen  car- 
bonate, has  also  been  described.1 

(2)  Ammonia  Method,  The  acid  (about  1  gram)  is 
dissolved  in  excess  of  alcoholic  potassium  hydroxide, 
and  made  up  to  250  cc  with  alcohol  of  the  same 
strength  (93  per  cent).  The  excess  of  alkali  is  neutralized 
by  carbonic  anhydride,  the  precipitated  carbonate  and 
bicarbonate  filtered  off  and  washed  with  50  cc  of 
alcohol  (98  per  cent).  The  alcohol  is  removed  from 
the  filtrate  and  washings  by  distillation,  and  the  re- 
sidue boiled  with  100  cc  of  ammonium  chloride 
solution  (10  per  cent).  The  potassium  salt  of  the  acid 
decomposes  the  ammonium  chloride,  and  the  liberated 
ammonia  is  determined  in  the  usual  manner.  The 
amount  of  alkali  carbonate  dissolved  by  100  cc  of 
alcohol  (93  per  cent)  is  equivalent  to  0.34  cc  of 
normal  acid ;  a  correction  for  this  must  be  applied 
and  also  one  for  the  ammonium  chloride  hydrolised 
by  the  water;  this  is  determined  by  a  blank  experi- 
ment, 100  cc  of  the  solution  being  boiled  during  the 
same  length  of  time,  1-2  hours,  as  in  the  actual  deter- 
mination.2 

The  method  gives  good  results  with  the  feebler  fatty 
acids,  and  is  especially  useful  when  the  dark  color  of 
the  solution  prevents  direct  titration. 

(3)  Hydrogen  Sulphide  Method.*  Compounds  contain- 
ing carboxyl  liberate  hydrogen  sulphide  from  certain 
metallo-hydrogen  sulphides  when  allowed  to   react  in 


1  Vohl  B.  10,  1807.     C  Jehn,  Ibid.  10,  2108. 

2  P.  C.  Mcllhiney,  J.  Am.  16,  408. 

8  F.  Fuchs,  M.  9,  1132,  1143  ;  11,  363. 


METIIOXYL,    ETHOXYL,    AND   CARBOXYL.  53 

an  atmosphere  of  hydrogen  sulphide,  according  to  the 
equation  : 

NaSH  +  R  .  COOH  +  xH5S  »->  RCOONa- 
+  H2S  +  xHaS 

two  volumes  of  hydrogen  sulphide  being  liberated  for 
each  volume  of  hydrogen,  replaceable  by  metal,  in  the 
original  compound.  Hydroxyl  hydrogen  in  phenols, 
alcohols,  and  hydroxy-acids  does  not  react  with  the 
metallo-hydrogen  sulphides. 

Preparation  of  the  Solution. 

The,  majority  of  alkali  salts  are  sparingly  soluble  in 
solutions  of  the  hydrosulphides,  hence  the  solution  of 
the  latter  must  not  be  so  concentrated  as  to  hinder 
the  reaction  from  being  rapidly  completed.  Potassium 
hydroxide  solution,  not  exceeding  10  per  cent,  is 
boiled  with  baryta  water  in  excess,  the  flask  closed, 
and  the  liquid  allowed  to  cool  and  deposit  barium 
carbonate.  The  clear  solution  is  now  poured  into  the 
vessel  to  be  used  for  the  analysis,  and  saturated  with 
hydrogen  sulphide. 

Method  of  Analysis. 
The  evolved  hydrogen  sulphide  may  be  determined  ; 

(a)  volume frically; 

(b)  by  titration. 

The  former  method  is  the  easier  and  is  therefore 
generally  employed. 


54 


RADICLES   IN   CARBON   COMPOUNDS. 


{a)    Volumetric  Determination. 
This    method   is   based   on  the    same    principle    as 
Victor    Meyer's  vapor   density   determination.       The 
apparatus,  Fig.  6,  consists  of   a  long-necked  flask  A, 

made  of  thick 
glass;  it  is  fitted 
with  a  rubber 
stoppers  through 
which  the  deliv- 
ery tube  B  pass- 
es, this  is  wide 
at  one  end  but 
terminates  in  a 
capillary  at  the 
other.  The  sec- 
ond hole  of  the 
stopper  is  closed 
by  means  of  a 
Fig.  6.  glass    rod     from 

which  the  vessel  containing  the  substance  is  suspended. 
Previous  to  the  determination  the  greater  portion  of 
the  flask  is  filled  with  hydrogen  sulphide,  but  the 
upper  portion  of  the  neck  and  the  delivery  tube  con- 
tain, air  which  is  expelled  by  the  evolved  hydrogen 
sulphide  and  collected  over  water  in  a  graduated  tube. 
The  substance  under  examination  is  dried,  finely 
powdered,  and  about  0.5  gram  weighed  into  the  small 
vessel,  the  glass  rod  being  pressed  into  the  rubber 
stopper  as  far  as  the  mark  1,  the  vessel  fitted  on  to  it 
by  means  of  the  stopper,  which,  with  the  delivery 
tube,  is  passed  air-tight  into  the  flask.  The  apparatus 
is  allowed  to  remain  for  a  few  moments  to  equalize  the 


METIIOXYL,    ETHOXYL,    AND    CARBOXYL. 


55 


temperature,  then  the  capillary  end  of  the  delivery- 
tube  is  dipped  into  water  below  the  open  end  of  the 
gas-measuring  vessel,  and  the  vessel  with  the  substance 
dropped  into  the  sulphide  solution  by  pushing  in  the 
rod  to  the  mark  2,  care  being  taken  not  to  alter  the 
position  of  the  stopper  itself.  The  evolution  of  hy- 
drogen sulphide  ceases  after  a  few  minutes.  The  same 
solution  may  be  employed  for  a  second  or  third 
determination,  but  each  time  the  delivery-tube  must 
be  previously  filled  with  dry  air.  The  weight  of  car- 
boxyl  hydrogen  G  is  calculated  from  the  results  by 
the  formula: 


V{b-W) 


760(1  -f-  0.00366/) 
V.(b  -w). 0.00000005895 


.0.0000896 


1  -f-  0.00366/ 

where  F=  the  observed  volume  of  air  displaced  in 
cc,  b  =  the  height  of  the  barometer,  and  w  the  ten- 
sion of  aqueous  vapor  at  the  observed  temperature  t. 


(b)    Titration  MetJwd. 

The  apparatus  employed  consists  of  a  short-necked 
flask  A,  Fig.  7,  fitted  with  a  rubber  stopper  and  glass 
rod  exactly  as  used  in  the 
preceding  method,  but  the 
delivery-tube  is  short  in  order 
to  expedite  the  expulsion  of 
air.  Before  the  stopper,  with 
the  substance  adjusted  in  the 
manner  described  above,  is  in- 
serted  into  the    flask,    tartaric 


Fig.  7- 


56  RADICLES   IN   CARBON    COMPOUNDS. 

acid  or  oxalic  acid  (about  0.25  gram)  is  dropped  into 
the  potassium  hydrogen  sulphide  solution  and  the 
stopper  immediately  inserted  air-tight  as  shown.  As 
soon  as  the  solution  of  gas  ceases  the  beaker  repre- 
sented in  the  figure  is  replaced  by  a  smaller  one  contain- 
ing concentrated  potassium  hydroxide  solution.  Some 
of  this  rises  in  the  tube  on  account  of  the  absorption 
of  the  gas,  but  the  error  so  introduced  compensates 
itself  at  the  end  of  the  experiment.  As  soon  as  the 
beaker  of  alkali  has  been  put  into  position,  the  sub- 
stance is  dropped  into  the  sulphide  solution  with  the 
same  precautions  as  observed  in  the  preceding 
method;  after  the  cession  of  the  gas  evolution,  which 
contimes  during  1-5  minutes,  the  pressure  is  adjusted 
by  lowering  the  beaker,  the  contents  are  poured  into 
a  large  flask,  and  the  beaker  and  evolution  tube 
washed.  The  alkali  and  washings  are  diluted  to  about 
500  cc,  neutralized  with  acetic  acid,  and  titrated  with 
iodine  solution  in  presence  of  starch.      Since 

H  =  H2S  =  I2, 

the  iodine  required,  divided  by  2  X  126.5,  gives  the 
weight  of  the  replaceable  hydrogen.  The  error  due 
to  the  insertion  of  the  glass  rod  from  mark  1  to  2  may 
be  determined  by  means  of  a  blank  experiment,  but  it 
is  so  small  as  to  be  usually  negligible.  More  recently 
the  action  of  substituted  phenols,  etc.,  on  alkali  hy- 
drogen sulphides  has  been  investigated1  with  the 
following  results: 

(1)   Haloid  substituted  phenols  with  one  hydroxyl 

1  Fuchs,  M.  11,  363. 


METHOXYL,    ETHOXYL,    AND   CARBOXYL.  $? 

group  are  without  action  on  the  sulphides,  but  if  two 
hydroxyl  groups  are  present  one  reacts. 

(2)  Only  the  paramononitro- phenols  react. 

(3)  Under  certain  conditions  the  presence  of  carboxyl 
groups  causes  the  phenolic  hydroxyl  to  decompose  the 
sulphides. 

(4)  In  general  lactones  do  not  react,  but  lactone-acids 
may  suffer  partial  resolution.1 

With  the  above  exceptions  the  method  provides  a 
ready  means  of  differentiating  carboxylic  hydrogen 
from  phenolic  or  alcoholic,  a  distinction  which  the  two 
preceding  methods  do  not  furnish  with  certainty. 

(4)  Iodine-oxygen  Method.'1  This  depends  on  the 
fact  that  even  feeble  organic  acids  liberate  iodine  from 
potassium  iodide  and  potassium  iodate  in  accordance 
with  the  equation  : 

6R.COOH+5KI  +  KI03^6R.COOK+3l9+3HaO. 

The  liberate  diodine,  in  presence  of  alkali,  evolves 
oxygen  from  hydrogen  peroxide : 

Ia  _|_  2KOH  »->  KOI  +  KI  +  HaO  and 
KOI  +  H20,  ^  KI  +  Hfi  +  Oa. 

The  oxygen  may  be  measured  in  a  modified  Wagner 
&  Knop's  Azotometer,3  or  in  any  other  convenient 
vessel. 

The  apparatus  consists  of  an  evolution  flask,  with 
a  small  cylinder  of  about  20  cc  capacity  fused  to  the 
middle  of  the  bottom  inside,  and  a  large  glass  cylinder 

1  H.  Meyer,  M.  19,  715. 
8  Baumann  and  Kux,  Z.  Anal.  Ch.  32,  129.         3  Ibid.  13,  389. 


58  RADICLES   IN   CARBON   COMPOUNDS. 

with  two  communicating  burettes  and  a  thermometer 
fastened  to  the  interior  of  the  cover.  The  cylinder 
and  burettes  are  filled  with  water,  the  latter  by  con- 
necting them  with  a  flask  from  which  water  is  forced 
by  air  pressure  from  a  hand  blower,  the  connecting 
tube  being  provided,  if  needful,  with  a  stop-cock.  The 
evolution  flask  is  closed  by  means  of  a  rubber  stopper 
carrying  a  tube  with  a  stop-cock  which  is  connected 
with  the  graduated  burette  •  below  the  stop-cock  in 
which  the  latter  terminates,  and  which  is  used  for  ad- 
justing the  pressure.  The  temperature  of  the  evolution 
flask  is  equalized  before  and  after  the  determination 
by  placing  it  in  water  of  the  same  temperature  as  that 
in  the  large  cylinder  enclosing  the  burettes.  The 
following  reagents  are  required : 

(i)  Potassium  iodide  ) 

,i  t.  .    ,   .     >  Absolutely  free  from  acid. 

(2)  "  lodate  )  J 

(3)  Hydrogen  peroxide  2-3  per  cent,  solution. 

(4)  Aqueous  potassium  hydroxide  solution  (1  : 1). 

(5)  Distilled  water,  recently  boiled  and  free  from 

carbonic  anhydride. 

The  determination  is  carried  out  in  the  following 
manner:  The  acid  (o.  1-0.2  gram)  is  mixed  with  finely 
divided  potassium  iodate  (about  0.2  gram),  potassium 
iodide  (2  grams),  and  water  (40  cc)  in  a  bottle  provided 
with  a  well-fitting  stopper,  and  allowed  to  remain  at 
the  ordinary  temperature  during  twelve  hours,  or  at 
70°-8o°  during  a  half  hour,  until  the  iodine  is  com- 
pletely precipitated.  The  solution  is  now  transferred 
to  the  outer  portion  of  the  evolution  flask,  the  bottle 
being  washed  with  not  more  than   10  cc  water.      Into 


METHOXYL,   ETHOXYL,    AND   CARBOXYL.  59 

the  inner  cylinder  of  the  evolution  flask  is  poured  by 
means  of  a  funnel  a  mixture  consisting  of  hydrogen 
peroxide  (2  cc)  and  potash  solution  (4cc),  made  imme- 
diately before  use  and  cooled  to  the  ordinary  tem- 
perature. The  evolution  flask  is  now  closed  with  its 
stopper  and  allowed  to  stand  in  water  during  ten 
minutes,  the  stopcock  of  the  burette  being  opened  to 
equalize  the  pressure;  at  the  end  of  this  time  it  is 
closed,  the  level  adjusted  to  the  zero  mark,  and  if  after 
five  minutes  no  change  takes  place  the  experiment  is 
proceeded  with,  otherwise  the  cooling  is  continued  dur- 
ing another  five  minutes.  When  equilibrium  is 
established  30-40  cc  of  water  are  run  from  the  burette 
in  order  to  reduce  the  pressure,  the  evolution  flask  is 
removed  from  the  cooling  vessel  by  means  of  a  cloth 
and  rotated  so  that  the  liquids  at  first  circulate  with- 
out mixing  and  are  then  suddenly  brought  into  contact. 
The  shaking  is  continued  vigorously  for  a  short  time 
and  the  flask  then  returned  to  the  cooling  vessel.  The 
evolution  of  oxygen  begins  at  once,  and  is  completed 
in  a  few  seconds ;  after  about  ten  minutes  the  pressure 
in  the  two  burettes  is  adjusted  and  the  volume  read 
the  number  of  cc  of  gas,  multiplied  by  the  value 
in  the  table  '  in  the  appendix  corresponding  to  the 
pressure  and  temperature,  gives  directly  the  weight 
of  carboxylic  hydrogen.  An  iodometric  method  for 
the  determination  of  acids  has  also  been  described,  for 
details  the  original  paper  should  be  consulted.3 

1  Baumann,  Z.  f.  ang.  Ch.  i8qi,  p.  328 
9  M.  Groger,  Ibid.  1890,  pp.  353,  385. 


Chapter  III. 

DETERMINATION   OF   CARBONYL   (CO). 

The  presence  of  the  carbonyl  group  in  aldehydes 
ketones,    etc.,    is    recognized   by   the    preparation   of 
derivatives  of  the  following  compounds: 
(i)   Phenylhydrazine. 

(2)  Hydroxylamine. 

(3)  Semicarbazide. 

(4)  Amidoguanidine. 

(5)  Paramidodimethylaniline. 

(i)     CARBONYL   DETERMINATION    BY    MEANS    OF 
PHENYLHYDRAZINE. 

The  method  is  divisible  as  follows : 

(A)  Preparation  of  phenylhydrazones  from  phenyl- 

hydrazine. 

(B)  Preparation  of  substituted  hydrazones. 

(C)  Indirect  method. 

(A)    Preparation  of  Phenylhydrazones.1 

Carbonyl  compounds  combine  with  phenylhydrazine 
forming  water  and  phenylhydrazones, 

C6H5NH.N:CRRi; 

dihydrazones,  with  the  hydrazine  groups  linked  to 
neighboring  carbon  atoms,  are  termed  osazones.  The 
reaction  usually  takes  place  most  readily  in  dilute  acetic 

1  E.  Fischer,  B.  16,  661,  2241,  foot-note  ;  17,  572  ;  22,  90. 

60 


DETERMINATION  OF  CARBONYL.        6l 

acid  solution,  often  at  the  ordinary  temperature, 
almost  always  by  heating  on  the  water-bath.  Frequent- 
ly it  is  advisable  to  allow  the  reaction  to  proceed  at 
the  ordinary  temperature  in  presence  of  concentrated 
acetic  acid,  which  acts  as  a  dehydrating  agent  and  in 
which  the  phenylhydrazones,  as  a  class,  are  sparingly 
soluble.1  E.  Fischer  dissolves  or  suspends  the  sub- 
stance in  water  or  alcohol,  and  adds,  in  excess,  a 
mixture  of  phenylhydrazine  hydrochloride  (i  part)  and 
crystallized  sodium  acetate  (1.5  parts)  dissolved  in 
water  (8—10  parts).  Free  mineral  acids  must  be  neutral- 
ized by  means  of  sodium  hydroxide  or  sodium  car- 
bonate, as  their  presence  hinders  the  reaction ;  the 
presence  of  nitrous  acid  is  particularly  hurtful  and  it 
must  be  removed  by  means  of  carbamide,  as  otherwise 
it  reacts  with  the  phenylhydrazine  and  forms  diazo- 
benzene  imide  and  other  oily  products.  Confusion  may 
also  be  caused  by  the  production  of  acetylphenyl- 
hydrazine  from  the  dilute  acetic  acid.9 

The  phenylhydrazones  gradually  separate  from  the 
solution  of  their  components  in  an  oily  or  crystalline 
form,  and,  in  the  latter  case,  are  purified  by  recrystal- 
lization  from  water,  alcohol,  or  benzene. 

It  is  often  desirable  to  heat  the  compound  under 
investigation  with  free  phenyhydrazine,  and  increased 
pressure  may  be  used  if  there  is  no  danger  of  phenyl- 
hydrazides  being  formed.3  The  product  is  poured  into 
water,  the  phenylhydrazone  removed  by  filtration, 
washed  with  dilute  hydrochloric  acid  to  free  it  from 
excess  of  phenylhydrazine,  and  recrystallized  ;  in  some 

1  Overton,  B.  26,  20.         2  Anderlini,  Ibid.  24,  1993,  foot-note. 
3  M.  14,  395. 


62  RADICLES   IN   CARBON  COMPOUNDS. 

cases  glycerol  is  employed  for  washing,  the  last  por- 
tions being  removed  by  water.1  Aliphatic  ketones 
react  readily  in  ethereal  solution,  and  the  water  which 
is  produced  may  be  absorbed  by  recently  ignited 
potassium  carbonate  or  calcium  chloride.  In  the  case 
of  ketophenols  or  ketoalcohols  the  hydroxyl  group 
should  be  acetylated  before  treatment  with  phenyl- 
hydrazine  ;  acids  are  usually  used  in  the  form  of  esters, 
but  the  sodium  salt  is  sometimes  employed  a  and  the 
condensation  promoted  by  the  addition  of  a  mineral 
acid.3  Hydrazones  may  also  be  prepared  from  oximes.4 
The  carbonyl  group  in  many  lactones  and  acid  an- 
hydrides condenses  with  phenylhydrazine,6  but  not 
with  hydroxylamine  ;B  on  the  other  hand,  many 
quinones,  such  as  anthraquinone,  do  not  react  with 
phenylhydrazine  or  only  with  one  molecular  proportion, 
as  in  the  case  of  naphthoquinone  and  phenanthra- 
quinone,  whilst  some,  such  as  benzoquinone  and  tolu- 
quinone,  oxidize  it  to  benzene.7  Ortho-disubstituted 
ketones  frequently  do  not  react  with  phenylhydrazine,8 
and  certain  unsaturated  ketoalcohols,  such  as  ethylic 
acetoacetate 9  and  ethylic  camphoroxalate,10  yield 
monophenylhydrazides,  the  ketonic  group  being  un- 

1  Thorns,  B.  29,  2988.  2  Bamberger,  Ibid.  19,  1430. 

8  Elbers,  Ann.  227,  353. 

4  Just,  B.  19,  1205.     von  Pechmann,  Ibid.  20,  2543,  foot-note. 

5  R.  Meyer  and  E.  Saul,  Ibid.  26,  1271.  Hemmelmayr,  M.  13,  667. 
Ephraim,  B.  26,  1376. 

8  v.  Meyer  and  Miinchmeyer,  Ibid.  19,  1706.      Holle,  J.  pr.  33, 
99-  '  S.  p.  538. 

8  Baum,  B.  28,  3209.     V.  Meyer,  Ibid.  29,  830,  836. 

9  Nef.  Ann.  266,  52. 

10  Bishop  Tingle,  Am.   Chem.   Journ.   20,  339.      A.  Tingle   and 
Bishop  Tingle,  Ibid.  21,  258. 


DETERMINATION    OF   CARBOXYL.  63 

affected.  Hydroxyketones  and  aldehydes  of  the  ali- 
phatic series  yield  phenylosazones,  a  portion  of  the 
phenylhydrazine  being  simultaneously  reduced  to 
aniline  and  ammonia.3 

A  method  has  been  described  for  the  purification 
of  commercial  phenylhydrazine.4 

(B)   Preparation  of  Substituted  Hydrazones. 

The  chief  substitution  product  of  phenylhydrazine 
which  has  hitherto  been  employed  for  the  preparation 
of  phenylhydrazones  is  the  parabromo-derivative. 

Preparation  ofParabromopJienylhydrazine.*  Phenyl- 
hydrazine  (20  grams)  is  poured  into  hydrochloric  acid 
(200  grams,  sp.  gr.  =  1.19)  and  the  precipitated  salt 
uniformly  distributed  throughout  the  liquid,  which  is 
cooled  to  0°  ;  bromine  (22.5  grams)  is  now  dropped  in, 
the  addition  occupying  10-15  minutes,  the  liquid 
being  well  shaken  during  this  time.  After  remaining 
during  twenty-four  hours  the  precipitate  is  removed, 
washed  with  a  little  cold  hydrochloric  acid,  dissolved 
in  water,  and  treated  with  sodium  hydroxide  in  excess. 
The  base  separates  in  flocculent  crystals  which  are 
extracted  with  ether,  the  ether  evaporated,  and  the 
residue  recrystallized  from  water.  The  hydrochloric 
acid  mother  liquor  contains  bromodiazobenzene  chlo- 
ride, which  is  reduced  by  the  addition  of  stannous  chlo- 
ride (60  grams) ;  the  precipitate  is  separated,  washed 
with  concentrated  hydrochloric  acid,  and  treated  with 
water  and  alkali,  the  base  being  collected  and  purified 

3  E.  Fischer  and  Tafel,  B.  20,  3386.  4  B.  Overton,  Ibid.  26,  19. 
5  Michaelis,  Ibid.  26,  2190. 


64  RADICLES   IN   CARBON   COMPOUNDS. 

in  the  manner  described  above.  The  yield  is  80  per 
cent.  Bromophenylhydrazine  requires  to  be  protected 
from  light  and  air;  it  should  be  kept  in  the  dark  in 
well-stoppered  colored  bottles  from  which  the  air  has 
been  displaced  by  carbonic  anhydride  or  coal-gas.  In 
these  circumstances,  if  the  compound  has  been  highly 
purified  and  dried,  it  may  be  retained  for  years  with- 
out change ;  colored  specimens  may  be  readily  puri- 
fied by  recrystallization  from  water,  to  which  a  few 
drops  of  sodium  hydroxide  should  be  added.  The 
pure  compound  melts  at  I07°-I09°,  the  acetyl  deriv- 
ative at  1 70V 

Substituted  PhenylJiydrazones. 

Parabromophenylhydrazine  is  well  adapted  for  the 
identification  of  certain  sugars,  such  as  arabinose, 
and  has  also  been  used  in  the  investigation  of  ionone 
and  irone;3  it  is  generally  employed  in  acetic  acid 
solution,  care  being  taken  to  prevent  the  liquid  from 
boiling,  as,  in  these  circumstances,  acetyl  parabromo- 
phenylhydrazine is  formed.4 

Paranitrophenylhydrazine  also  gives  well  defined 
condensation  products  with  many  aldehydes  and 
ketones  which  serve  for  their  identification.  The 
reaction  usually  proceeds  in  aqueous  solution  with 
the  hydrochloride,  but  the  free  base  in  alcohol  or 
acetic  acid  may  be  employed.5 

In  addition  the  following  substituted  phenyl- 
hydrazines    have    been    used    for  the    production    of 

1  Tiemann  and  Krtiger.  9  E.  Fischer,  B.  24,  4221,  foot-note. 

8  Tiemann  and  Krtiger,  Ibid.  28,  1755.  4  Ibid.  26,  2190. 

6  E.  Bamberger    &    Kraus,  Ibid.    29,    1834.      Bamberger,    Ibid. 
32,  1806.     E.  Hyde,  Ibid.  32,  1810. 


DETERMINATION  OF  CARBONYL.  65 

phenylhydrazones :  dibromo-,  symmetrical  tribromo-, 
tetrabromo-,  parachloro-,  pariodo-,  and  metadiiodo-,1 
whilst  some  derivatives  of  diphenylhydrazine  have  also 
been  described.3 

(C)  Indirect  Method.3 

This  method  depends  on  allowing  the  aldehyde  or 
ketone  to  react  with  excess  of  phenylhydrazine ;  the 
excess,  together  with  any  hydrazide,  is  then  oxidized 
by  means  of  boiling  Fehling's  solution,  the  liberated 
nitrogen  being  collected ;  phenylhydrazones  are  not 
decomposed  by  this  treatment. 

The  reagents  required  are  as  follows: 

Copper  sulphate  solution  (70  grams  Cu  So4.5HaO  in 
1  liter).  Alkaline  solution  of  sodium  potassium  tartrate, 
made  by  dissolving  350  grams  of  the  tartrate,  and  260 
grams  potassium  hydroxide  in  1  liter;  these  two 
solutions  are  mixed  in  equal  volumes  to  form  the 
Fehling's  solution. 

Sodium  acetate  (10  per  cent  solution). 

Phenyldrazine  hydrochloride  (5  per  cent  solution.) 
The  analysis  is  made  by  mixing  the  compound  under 
examination  (0.1-0.5  gram)  with  an  accurately  meas- 
ured quantity  of  the  phenylhydrazine  hydrochloride 
solution  (1  part)  and  the  sodium  acetate  solution  (i£ 
parts)  in  a  1 00  cc  measuring  flask.  The  phenylhy- 
drazine hydrochloride  is  taken,  if  possible,  in  quantity 
sufficient  to  yield  15-30  cc  nitrogen.  Water  is  now 
added  to  the  mixture  in  the  flask  so  as  to  make  the 
volume  about  50  cc,  and  the  liquid   is  heated    on  the 

1  A.  Neufeld,  Ann.  248,  93.  2  R.  Overton,  B.  26,  10. 

8  H.  Strache,  M.  12,  524;  13,  299,   Benedikt  and  Strache,  Ibid. 
14,  270. 


66  RADICLES   IN   CARBON   COMPOUNDS. 

water-bath  during  15-30  minutes;  it  is  then  cooled, 
diluted  to  the  mark,  well  shaken,  50  cc  transferred  to 
the  dropping  funnel  T,  Fig.  8,  and  the  determination 


Fig.  8. 

conducted  in  the  manner  described  below.  The  flask 
A  has  a  capacity  of  750-1000  cc,  and  contains  200  cc 
of  Fehling's  solution,  which  is  boiled  whilst  a  rapid 
current  of  steam  is  blown  in  from  the  flask  B.  The 
tubes  D  and  R  must  be  flush  with  the  rubber  stoppers 
so  as  to  promote  the  removal  of  air.  The  tube  R  is 
in  two  pieces,  joined  by  the  rubber  tube  K;  its  lower 
end  is  covered  with  a  piece  of  rubber-tube  E  and  dips 
below  water  in  the  dish  W.  The  current  of  steam  is 
continued  until  the  bubbles  of  gas  collected  are  very 
small,  it  is  impossible,  in  a  reasonable  time,  to 
remove  all  the  air  and  a  titration  of  the  phenylhy- 
drazine  hydrochloride  solution  is  made,  previous  to 
the  actual  determination,  so  as  to  allow  for  this  error. 
1  gram  of  the  salt  eliminates  about  155  cc  nitrogen, 
therefore,  for  the  titration,  10  cc  of  the  solution  is 
accurately    measured    out,    mixed    with    the    needful 


DETERMINATION   OF   CARBON YL.  67 

proportion  of  sodium  acetate  solution,  diluted  to  100 
cc,  and  50  cc  transferred  to  the  dropping  funnel;  the 
end  of  this  is  drawn  out  at  5  and  cut  off  at  an  angle  so 
as  to  avoid  the  collection  of  bubbles  of  gas ;  before 
the  funnel  is  fixed  in  place  the  stem  is  filled  with 
water.  When  the  greater  portion  of  the  air  has  been 
removed  from  the  apparatus  in  the  manner  described 
above,  the  phenylhydrazine  salt  is  allowed  to  mix  with 
the  Fehling's  solution,  care  being  taken  to  prevent 
the  water  flowing  from  IV'mto  A.  When  all  has  been 
added  the  funnel  is  washed  out  twice  with  hot  water, 
which  is,  of  course,  also  allowed  to  run  into  A.  If 
the  boiling  is  sufficiently  brisk  the  evolution  of  nitro- 
gen is  completed  in  2-3  minutes.  As  soon  as  the 
bubbles  are  as  small  as  those  of  the  air  at  the  com- 
mencement of  the  experiment  the  heating  is  stopped, 
the  hot  water  in  W  replaced  by  cold,  the  excess  escap- 
ing into  the  dish  C  and  the  measuring  tube  removed, 
to  a  cylinder  of  cold  water.  The  actual  determina- 
tion is  made  immediately  after  the  completion  of  the 
blank  experiment  and,  if  necessary,  repeated  a  second 
or  third  time;  since  200  cc  Fehling's  solution  readily 
liberates  150  cc  nitrogen,  the  quantity  taken  in  A 
amply  suffices  for  three  or  four  carbonyl  determina- 
tions. 

As  benzene  is  produced  during  the  oxidation  of  the 
phenylhydrazine,  a  drop  of  it  will  be  found  floating 
on  the  surface  of  the  water  inside  the  measuring  tube; 
this  may  be  allowed  for  in  measuring  the  gas  or  it  may 
be  removed.  In  the  former  case  a  little  more  benzene 
is  introduced  into  the  tube  by  means  of  a  bent  pipette, 
and,  after  remaining  during  a  short  time,  the   volume 


68 


RADICLES    IN    CARBON    COMPOUNDS. 


of  nitrogen  is  read  off  in  the  ordinary  manner ;  its 
reduction  to  o  °  and  760  mm  may  be  made  by  the 
help  of  the  following  tLble,  the  values  in  the  second 
column  being  subtracted  from  the  ob- 
served height  of  the  barometer  : 


mperature. 

Tension  of  benzene  -j-  water 

i5° 

C. 

72  7  mm. 

16 

76.8 

17 

80.9 

18 

85.2 

19 

89-3 

20 

93-7 

21 

98.8 

22 

IO3.9 

23 

IO9. 1 

24 

H4-3 

25 

119.7 

The  values  given  above  are  in  part 
obtained  by  interpolation  from  Reg- 
nault's  results  and  are  therefore  subject 
to  error;  for  this  reason,  and  on  account 
of  the  high  vapor  tension  of  benzene 
its  removal  is  advisable.1  To  accom- 
Fig    9.  plish  this  alcohol  is  added  to  the  tube 

of  nitrogen,  which  is  placed  in  a  cylinder  of  about  its 
own  length  filled  with  water  (Fig.  9).  A  glass  tube 
5  mm.  in  diameter  is  bent  into  the  form  of  a  U  as 
shown  in  the  figure,  the  smaller  limb  terminating  in  a 
jet  and    being  of    such  length    that,    when   the  bent 


Benedikt  and  Strache,  M.  14,  373. 


DETERMINATION   OF   CARBONYL.  69 

portion  rests  on  the  bottom  of  the  cylinder,  the  jet  is 
several  cm  below  the  surface  of  the  water.  The  longer 
limb  rises  about  40  cm  above  the  surface  of  the  water 
and  is  connected  at  the  end  by  means  of  a  piece  of 
thick  walled  rubber  tube  with  a  dropping  funnel.  The 
U  tube  is  completely  filled  with  water  and  placed  in 
the  position  shown  in  the  figure.  Alcohol  (about 
200  cc)  is  now  allowed  to  flow  from  the  funnel 
into  the  measuring  tube;  it  issues  from  the  jet  in 
a  fine  stream  and  absorbs  the  benzene  vapor  pres- 
ent in  the  nitrogen  as  well  as  that  floating  on  the 
water;  the  alcohol  is  removed  in  a  similar  manner  by 
washing  with  at  least  400  cc  water,  and  the  tube  of 
nitrogen  then  removed  to  another  cylinder  of  water, 
where,  after  a  suitable  interval,  the  volume  of  gas  is 
read.  The  amount  of  carbonylic  oxygen  O  is  ob- 
tained from  the  volume  of  nitrogen,  corrected  to  o° 
and  760  mm,  by  the  expression  :  O  —  (g.  V.  —  2  V0.). 

15.96    ioc>  ^      ,     r_  Tr  0.07178 

°-0012562  *  2~t^2  '  ~Tio  =  °=&  V'  ~2V»~-^      *> 

where  g  is  the  weight  of  phenylhydrazine  hydro- 
chloride taken,  V  the  volume  of  nitrogen  evolved  by 
1  gram  of  this  salt,  5  the  weight  of  the  compound  em- 
ployed, and  V0  the  volume  of  nitrogen  obtained  at 
N.  T.  P.  The  theoretical  value  of  V  is  154.63CC,  but 
the  value  employed  in  the  calculation  is  that  obtained 
in  the  blank  experiment. 

If  the  phenylhydrazone  is  in  soluble  in  water  or 
dilute  alcohol,  or  if  sparingly  soluble  phenylhy- 
drazides  are  formed,  the  preparation  of  the  phenylhy- 
drazone must  be  made  in  alcoholic  solution  ;    in  this 


yo  RADICLES    IN    CARBON    COMPOUNDS. 

case  the  weight  of  the  column  of  liquid  in  the  funnel 
T,  Fig.  8,  will  not  be  sufficient  to  overcome  the 
pressure  of  steam  in  the  flask  A.  This  difficulty  may 
be  surmounted  by  fitting  the  open  end  of  the  funnel 
with  a  rubber  stopper,  carrying  a  tube  and  stop-cock. 
By  blowing  through  the  tube  the  alcoholic  liquor  is 
forced  into  the  flask,  but  great  care  is  necessary,  as 
the  sudden  evolution  of  alcoholic  vapor  may  eject 
liquid  from  flask  A  to  B,  or  may  even  lead  to  an  ex- 
plosion. A  second  objection  to  the  use  of  alcohol  is 
that,  at  its  boiling-point,  ketones  do  not  always  react 
quantitatively  with  phenylhydrazinc.  Both  difficulties 
may  be  overcome  by  the  use  of  recently  boiled  amylic 
alcohol  as  solvent,  the  portion  of  it  which  passes  over 
with  the  nitrogen  being  subsequently  removed  simul- 
taneously with  the  benzene,  and  in  the  same  manner, 
by  washing  with  alcohol  and  water. 

(2)    PREPARATION    OF   OXIMES.1 

In  the  preparation  of  oximes  the  hydroxylamine  is 
employed  in  the  form  of  the  free  base,  the  hydro- 
chloride, as  potassium  hydroxy laminesulphonatc,  or 
zinc  dihydroxylamine  hydrochloride.  Aldoximes  are 
obtained  by  treating  aldehydes  with  an  equimolecular 
proportion  of  hydroxylamine  hydrochloride  in  con- 
centrated aqueous  solution,  adding  sodium  carbonate 
(0.5  mol.),  and  allowing  the  mixture  to  remain  at  the 
ordinary  temperature  during  £-8  days.  The  oxime 
is  extracted  with  ether,  the  solution  dried  over  calcium 


1  V.    Meyer    and   Janny,    B.    15,    1324,    1525.     Janny,    Ibid.    15, 
2778;   16,  170. 


DETERMINATION   OF   CARBONYL.  7 1 

chloride,  and,  after  the  removal  of  the  ether,  the 
residue  rectified.  An  aqueous-alcoholic  solution  is 
used  for  aldehydes  insoluble  in  water,  and  those  that 
are  readily  oxidizable,  such  as  benzaldehyde,  are 
treated  in  flasks  from  which  the  air  has  been  removed 
by  means  of  carbonic  anhydride.1  Oximes  of  the 
carbohydrates,  which  are  so  readily  soluble  in  water 
that  they  cannot  be  separated  from  the  inorganic  salts 
resulting  from  the  use  of  hydroxylamine  hydrochloride 
and  sodium  carbonate  or  sodium  hydroxide,  are  treated 
with  the  calculated  quantity  of  free  hydroxylamine 
in  alcoholic  solution ;  after  several  days  the  oxime 
gradually  crystallizes  out.a  Alcoholic  solution  of 
hydroxylamine  is  prepared  by  intimately  mixing  the 
hydrochloride  with  the  necessary  quantity  of  potassium 
hydroxide  together  with  a  little  water,  and  then 
adding  absolute  alcohol,  the  clear  liquid  is  after- 
wards separated  from  the  precipitated  potassium 
chloride.3  The  solution  gradually  acquires  a  slight 
yellow  color,4  which  may  be  obviated  by  substituting 
sodium  ethoxide  for  the  potassium  hydroxide. 

Ketoximes  are  usually  formed  less  readily  than  the 
aldoximes ;  for  their  preparation  the  ketone  is  mixed 
with  sodium  acetate  and  hydroxylamine  hydrochloride 
in  aqueous  or  alcoholic  solution  in  the  necessary  propor- 
tions, and  the  liquid  heated  on  the  water-bath  during 
1-2  hours,  or  the  ketone,  in  alcoholic  solution,  may 
be  heated  in  a  sealed  tube  with  the  hydrochloride  at 
i6o°-i8o°     during    8-10    hours,5   but     sometimes    in 

1  Petraczek,  B.  15,  2783.  »  Wohl,  Ibid.  24,  994.     S.,  p.  367. 

3  Volhard,  Ann.  253,  206.         4  Tiemann,  B.  24,  994. 
6  Homolka,  Ibid.  19,  1084. 


72  RADICLES   IN   CARBON   COMPOUNDS. 

these  circumstances,  instead  of  the  oximes  derivatives 
of  them  are  formed  by  intramolecular  rearrangement.1 
In  many  cases  it  is  highly  advantageous  to  allow  the 
carbonyl  derivative  and  the  hydroxylamine  to  react 
in  strongly  alkaline  solution ;  the  proportions  which 
usually  give  the  best  results  are  ketone,  in  alcoholic 
solution  (i  mol),  hydroxylamine  hydrochloride  (1.5-2 
mol),  alkaline  hydroxide  (4.5-6  mol);  the  last  two  are 
dissolved  in  the  smallest  requisite  quantity  of  water.2 
The  reaction  is  often  completed  at  the  ordinary 
temperature  in  a  few  hours;  occasionally  heating  on 
the  water-bath  is  desirable.  This  method  cannot  of 
course  be  used  with  ketones  or  aldehydes  that  are 
attacked  by  alkali,  nor  in  the  preparation  of  dioximes 
which  readily  change  into  their  anhydrides  in  the 
presence  of  alkali.  In  such  cases  an  acid  liquid  may 
be  employed.  Quinone  furnishes  an  example  of  this. 
In  alkaline  solution  it  is  reduced  by  hydroxylamine 
to  hydroquinone,  whilst  in  aqueous  solution,  in  pres- 
ence of  hydrochloric  acid  and  hydroxylamine  hydro- 
chloride, a  dioxime  is  formed.3  Some  compounds, 
such  as  phenylglyoxalic  acid,  yield  oximes  both  in 
alkaline  and  acid  solution.4  Oximes  of  ketonic  acids 
may  be  obtained  by  treating  the  alkali  salt  in  neutral 
aqueous  solution  with  hydroxylamine  hydrochloride ; 
the  precipitation  of  oxime  usually  commences  at  once, 
especially  if  the  liquid  is  warmed.6  Sometimes  it  is 
advisable  to  convert  the  acid  into  its  methyl  ester  and 


1  Thorp,  B.  26,  1261.  2  Auwers,  Ibid.  22,  609. 

3  Nietzki  and  Kehrmann,  Ibid.  20,  614.  4  S.  p.  370. 

5  Bamberger,  Ibid.  19,  1430. 


DETERMINATION  OF  CARBONYL.        73 

avoid  the  use  of  excess  of  hydroxylamine  hydrochloride 
so  as  to  prevent  the  formation  of  nitriles.1 

Potassium  hydroxylamine  sulpJionate,  supplied  by 
the  "  Badischen  Anilin-  und  Sodafabrik,"  under  the 
name  "  Reducirsalzes,"  has  been  employed,  in  aqueous- 
alcoholic  solution,  for  the  preparation  of  oximes ;  2  in 
presence  of  free  alkali  it  is  hydrolysed,  and  the  liber- 
ated hydroxylamine  acts  in  the  nascent  state  on  the 
carbonyl  compounds.3  It  also  possesses  the  advantage 
of  cheapness. 

Zinc diJiydroxylamine hydrochloride ',  ZnCla.2  N  HaOH, 
has  been  used  chiefly  for  the  preparation  of  ketoximes  4 
as  its  resolution  into  hydroxylamine  and  anhydrous 
zinc  chloride  facilitates  the  elimination  of  water.  It 
is  prepared5  by  adding  zinc  oxide  (1  part)  to  hydrox- 
ylamine hydrochloride  (2  parts)  in  boiling  alcoholic 
solution.  The  boiling  is  continued  in  a  reflux  appa- 
ratus for  a  few  moments,  and  the  liquid  allowed  to 
cool.  The  compound  is  deposited  as  a  crystalline 
powder  which  dissolves  sparingly  in  water  or  alcohol, 
but  readily  in  solutions  of  hydroxylamine  hydro- 
chloride. 

Ortho-  and  paraquinones  and  metadiketones  cease 
to  react  with  hydroxylamine  if  several  atoms  of  hy- 
d  ogen  in  the  ortho-position  are  replaced  by  haloid 
atoms  or   alkyl   groups.0      Aromatic    ketones   of    the 

formula    (CH3.C)aC.COR,    where    R  =  phenyl   or    an 

1 

1  Garelli,  Gazz    21,  2%  Ibid.  2173.  2  Kostanecki,  B.  22,  1344, 

3  Raschig,  Ann.  241,  187. 

4  Crismer,  Bull.  soc.  chim.  [3],  3,  114.  6  B.  23,  R.  223. 

6  Kehrmann,  Ibid.  21,  3315.  Herzig  and  Zeisel,  Ibi  i.  21,  3494. 
Cf.  Ibid.  22,  1344. 


74  RADICLES   IN   CARBON   COMPOUNDS. 

alcohol  radicle,  are  also  incapable  of  forming  oximes;1 
indeed,  the  presence  of  carbonyl,  which  does  not  yield 
oximes,  in  such  compounds  as  acids,2  amides,'  or 
esters4  may,  by  the  production  of  hydroxamic  acids, 
lead  to  erroneous  results.  The  statement  that  alkyl 
salicylates  and  hydroxylamine  give  salicylhydroxamic 
acid  requires  further  investigation.4  The  unsaturated 
ketoalcohol  camphoroxalic  acid 

C:C.OH.CO.OH 

c-H-<co 

yields  an  additive  compound 

CH.C.OH.CO.OH 
8    14<CO  NH.OH 

with  hydroxylamine,5  and  it  has  been  subsequently 
shown  that  certain  unsaturated  ketones,  such  as  pho- 
rone,  behave  in  a  similar  manner.6 

(3)    PREPARATION    OF    SEMICARBAZONES.7 

The  formation  of  well-crystallized  derivatives  of 
semicarbazide  has  proved  extremely  useful  in  the 
investigation  of  terpene  compounds  which  often  yield 
liquid  oximes,  and  phenylhydrazones  that  only  crys- 

1  V.  Meyer,  B.  29,  836.  Feit  and  Davies,  Ibid.  24,  3546 
Biginelli,  Gazz.  24,  1,  437.  Claus,  J.  pr.  45,  383.  Baum,  B.  28, 
3209. 

2  Nef,  Ann.  258,  282.  3  C.  Hoffmann,  B.  22,  2854. 

4  Jeanrenaud,  Ibid.  22,  1273. 

5  Bishop  Tingle,  Am.  Chem.  Journ.  19,  408. 

6  C.  Harries  and  F.  Lehmann,  B.  30,  231,  2726. 

7  Baeyer  and  Thiele,  Ibid.  27,  191 8. 


DETERMINATION  OF  CARBONYL.        75 

tallize  with  difficulty  and  readily  undergo  decomposi- 
tion. 

Preparation  of  Semicarbazide  Salts. 

(A)  Semicarbazide  Hydrochloride 
NH,.CO.NH.NH2.HCl 

is  prepared  from 

(a)  Hydrazine  sulphate ; 1 
(p)  Nitrocarbamide.'1 

(a)  Hydrazine  sulphate  (13  grams)  is  dissolved  in 
water  (100  cc),  and  neutralized  with  dry  sodium  car- 
bonate (5.5  grams),  when  cold  potassium  cyanate  (8.8 
grams)  is  added  and  the  solution  allowed  to  remain 
overnight.  A  small  quantity  of  hydrazodicarbonamide, 
NH,.CO.NH.NH.CO.NH2,  s  deposited  which  is  some- 
what augmented  on  acidifying  with  dilute  sulphuric 
acid.  The  amide  is  removed  and  the  acid  liquid  well 
shaken  with  benzaldehyde ;  the  precipitate  of  benzal- 
semicarbazone  which  forms  is  separated  and  well 
washed  with  ether.  It  is  now  carefully  heated  on  the 
water-bath,  in  portions  of  20  grams,  with  concentrated 
hydrochloric  acid  (40  grams),  sufficient  water  being 
added  to  cause  the  hot  liquid  to  become  clear;  the 
benzaldehyde  is  removed  by  repeatedly  extracting  the 
hotliquid  with  benzene  ;  when  coldthe  aqueous  solution 
deposits  small  needles  of  semicarbazide  hydrochloride, 
which  are  removed,  dried,  and  recrystallized  from 
dilute  alcohol.      The  purified  compound  forms  prisms 

1  Thiele  and  O.  Stange,  B.  28,  32. 

2  Thiele  and  Heuser,  Ann.  288,  312. 


j6  RADICLES   IN   CARBON   COMPOUNDS. 

which  decompose  at  1730.  The  mother-liquors  yield 
a  further  quantity  of  the  benzal  derivative  when  treated 
with  benzaldehyde. 

(b)  Commercial  nitrocarbamide  (225  grams)  is  mixed 
with  concentrated  hydrochloric  acid  (1700  cc),  a  little 
ice  added,  and  the  liquid  made  into  a  paste  by  the 
successive  additions  of  small  quantities  of  zinc-dust 
and  ice ;  constant  stirring  is  necessary,  and  the  tem- 
perature must  not  exceed  o°.  The  operation  may  be 
carried  out  in  an  enamelled  dish  cooled  by  means  of 
a  freezing  mixture ;  when  it  is  completed  the  product 
is  allowed  to  remain  for  a  short  time,  the  excess  of 
zinc-dust  removed,  and  the  filtrate  saturated  with 
sodium  chloride.  Sodium  acetate  (200  grams)  is  now 
added,  together  with  acetone  (100  grams),  and  the 
liquid  placed  on  ice  or  in  a  freezing  mixture.  In  the 
course  of  several  hours  a  double  salt  of  zinc  chloride 
and  acetone  semicarbazide  crystallizes  out,  it  is 
collected  and  washed  first  with  sodium  chloride  solu- 
tion and  finally  with  a  little  water.  The  yield  is 
40-55  per  cent.  The  zinc  compound  (200  grams)  is 
digested  with  concentrated  ammonium  hydrate  (350  cc) 
and  after  some  time  the  liquid  is  filtered ;  the  residue 
consists  of  acetone  semicarbazone,  which  is  converted 
into  semicarbazide  salts  in  the  manner  described  above 
for  the  benzal  derivative.  Many  ketones  do  not 
readily  react  with  semicarbazide  hydrochloride  and 
the  products  obtained  from  some  may  contain  chlorine ; 
in  such  cases  semi-carbazide  sulphate  should  be 
employed. 


DETERMINATION   OF  CARBONYL.  JJ 

(B)  Preparation  of  Scrmicarbazide  Sulphate} 

The  filtrate  from,  hydrazodicarbonamide,  prepared 
in  the  manner  described  above,  is  cautiously  made 
alkaline  and  shaken  with  acetone ;  the  acetone  semi- 
carbazone  which  is  deposited  is  mixed  with  alcohol, 
and  treated  with  the  calculated  quantity  of  sulphuric 
acid ;  the  sulphate  crystallizes  out  and  is  purified  by 
washing  with  alcohol. 

Preparation  of  Semicarbazcnes* 

Semicarbazide  hydrochloride,  dissolved  in  the 
minimum  quantity  of  water,  is  mixed  with  the  cal- 
culated amount  of  potassium  acetate  in  alcoholic 
solution,  and  the  ketone  added,  together  with  water 
and  alcohol  sufficient  to  give  a  clear  homogeneous 
liquid.  This  is  allowed  to  remain  until  the  completion 
of  the  reaction,  which  is  recognized  by  the  deposition 
of  crystals  when  the  mixture  is  diluted  with  water, 
and,  as  in  the  case  of  hydroxylamine,  may  require 
from  a  few  minutes  to  four  or  five  days.  Sometimes 
it  happens  that  the  deposit  produced  is  oily  and 
only  solidifies  after  several  hours.  The  use  of  semi- 
carbazide sulphate  is  illustrated  by  the  preparation  of 
ionone  semicarbazone,  which  cannot  be  obtained  from 
the  hydrochloride.  The  sulphate  is  used  in-  a  finely 
divided  form  and  added  to  glacial  acetic  acid  in  which 
the  equivalent  quantity  of  sodium  acetate  has  been 
dissolved  ;  after  remaining  at  the  ordinary  temperature 
during  twenty-four  hours,   the   solution  of  ionone  is 

1  Tiemann  and  Kriiger,  B.  28,  1754.      2  Baeyer,  Ibid.  27,  1918. 


7%  RADICLES   IN   CARBON   COMPOUNDS. 

added,  and  the  liquid  allowed  to  remain  three  days 
longer.  The  product  is  poured  into  a  considerable 
volume  of  water,  extracted  with  ether,  and  the  ether 
freed  from  acetic  acid  by  treatment  with  sodium  car- 
bonate solution.  After  drying  and  removal  of  the 
ether  the  residue  is  treated  with  ligroin  to  remove 
some  impurities,  and  the  remaining  product  crystallized 
from  a  mixture  of  benzene  and  ligroin. 

Should  a  ketone  not  yield  a  crystalline  semicarbazide 
it  is  advisable  to  treat  it  with  amidoguinadine  picrate, 
as  the  resulting  compounds  are  distinguished  by  the 
ease  with  which  they  crystallize. 

(4)  PREPARATION  OF  AMIDOGUINADINE  DERIVATIVES.1 

Preparation  of  Amidoguinadine  Salts."1 

Nitroguinadine  (208  grams)  is  mixed  with  zinc-dust 
(700  grams)  and  sufficient  ice  and  water  to  form  a 
stiff  paste ;  to  this  commercial  glacial  acetic  acid 
(124  grams),  diluted  with  its  own  volume  of  water, 
is  added,  the  mixture  is  well  stirred,  and  great  care 
taken  to  add  ice  so  that  during  the  2-3  minutes 
required  for  the  addition  of  the  acid  the  temper- 
ature shall  not  exceed  o°.  The  temperature  is  now 
allowed  to  rise  gradually  to  Jo° ;  at  this  stage  the 
mixture  is  viscid  and  has  a  yellow  color  due  to  an  in- 
termediate product.  The  temperature  is  maintained 
at  40°-45°  until  a  little  of  the  filtered  liquid  ceases  to 
yield  a  red  color  with  sodium  hydroxide  and  a  ferrous 
salt.      The  conclusion  of  the  operation   is  usually  in- 

1  Baeyer,  B.  27,  1919.  2  Thiele,  Ann.  270,  23. 


DETERMINATION  OF  CARBONYL.        79 

dicated  by  evolution  of  gas  and  the  formation  of  a 
frothy  scum  on  the  surface  cf  the  liquid.  The  product 
is  filtered,  the  residue  well  washed  with  water,  the 
washings  and  filtrate  mixed  with  hydrochloric  acid 
sufficient  to  liberate  the  acetic  acid,  and  the  whole 
concentrated  to  the  smallest  possible  bulk;  it  is  then 
treated  with  alcohol,  again  evaporated  to  expel  water, 
and  the  solid  boiled  out  with  alcohol;  this,  when 
cold,  deposits  amidoguinadine  hydrochloride,  which  is 
further  purified  by  rccrystallization  from  alcohol  to 
which  animal  charcoal  has  been  added.  The  pure 
salt  melts  at  1630. 

Preparation  of  Amidoguinadine  Bicarbonate.1 

The  liquid  obtained  by  the  reduction  of  nitroguina- 
dine  with  zinc-dust  and  acetic  acid  is  maintained 
slightly  acid  with  acetic  acid,  evaporated  to  about 
500  cc,  cooled,  and  treated  with  concentrated  sodium 
or  potassium  bicarbonate  solution  to  which  a  little 
ammonium  chloride  has  been  added  to  prevent  the 
deposition  of  any  zinc.  The  amidoguinadine  salt  is 
completely  precipitated  in  twenty-four  hours;  it  is 
sparingly  soluble  in  hot  water  but  suffers  decomposi- 
tion, and  when  slowly  heated  it  melts  and  decom- 
poses at  1720. 

The  nitrate  and  the  normal  and  hydrogen  sulphates 
are  prepared  in  a  similar  manner. 

1  Thiele,  Ann.  302,  333. 


80  RADICLES   IN   CARBON   COMPOUNDS. 

Preparation  of  Amidogninadine  Picrale  Derivatives. 

Amidoguinadine  hydrochloride  is  dissolved  in  a 
small  quantity  of  water  containing  a  trace  of  hydro- 
chloric acid  and  the  ketone  added  together  with  suf- 
ficient alcohol  to  give  a  clear  solution.  The  reaction 
is  completed  by  boiling  for  a  short  time.  The  product 
is  treated  with  water  and  sodium  hydroxide  solution 
in  excess,  and  the  liquid  base  extracted  by  means  of 
ether.  The  ethereal  solution  is  separated,  the  ether 
removed,  the  residual  oil  suspended  in  water  and 
treated  with  picric  acid  in  aqueous  solution,  the  picrate 
is  quickly  deposited  in  granular  crystals  which  are 
purified  by  recrystallization  from  concentrated  or 
dilute  alcohol. 

Some  carbohydrate  derivatives  of  amidoguinadine 
are  known.1 

PARAMIDODIMETHYLANILINE   DERIVATIVES. 

Condensation  products  of  aldehydes  and  paramidodi- 
methyl  aniline  may  be  prepared  by  mixing  the  con- 
stituents with  or  without  the  addition  of  alcohol. 
The  temperature  of  the  liquid  rises  spontaneously, 
and  the  condensation  product  usually  separates  in 
crystals.5 

1  Wolff  and   Herzfeld,  Z.    Rub.  1895,  743-     Wolff,   B.  27,  971; 
28,  2613. 

2  A.  Cahn,  Ibid.  17,  2938.    The  literature  of  this  subject  is  given 
in  M.  and  J.  II,  p.  515. 


Chapter    IV. 

DETERMINATION  OF  THE  AMINO  NH2;  NITRILE 
CN;  AMIDE  CO.NH2;  IMIDE  NH;  METHYL  IM1DE 
N.CH3;  AND  ETHYL  IMIDE  N.C2H5  GROUPS. 

DETERMINATION  OF  THE  AMINO  GROUP  (NH,). 

Different  methods  are  employed  for  the  determina- 
tion of  the  amino  group  according  to  whether  the 
compound  is  an  aromatic  or  aliphatic  amine. 

(A)  Determination  of  Aliphatic  Amino  Groups. 
These  are  determined: 

(i)  By  means  of  nitrous  acid. 

(2)  By  analysis  of  tJie  salts  and  double  salts. 

(3)  By  acctylation. 

(1)  Nitrous  Acid  MetJiod. — Aliphatic  amines  react 
with  nitrous  acid  in  accordance  with  the  equation 

RNH,  +  HNO,  »-»  ROH  +  N,  +  H20. 

The  first  method  suggested  for  the  determination  of 
the  nitrogen  consisted  in  liberating  it  in  an  atmosphere 
of  nitric  oxide,  which  was  then  absorbed  by  means  of 
ferrous  sulphate  solution.1  The  following  process  is 
much  more  convenient.      The  substance,  dissolved  in 

1  R.  Sachsse  and  W.  Kormann,  Landwirthsch.  Vers.-Stationen, 
17,  321.     Z.  anal.  Ch.  14,  380. 

81 


82  RADICLES   IN    CARBON   COMPOUNDS. 

just  sufficient  dilute  sulphuric  acid  to  give  a  neutral 
solution,  is  placed  in  a  flask  provided  with  a  trebly 
bored  stopper.  If  possible  a  distillation  bulb  should 
be  employed  having  a  capillary  tube  fused  to  it.  A 
dropping  funnel  is  fitted  to  the  stopper  of  the  flask, 
the  leg  being  drawn  out,  bent  upwards,  and  passed 
below  the  surface  of  the  liquid ;  it  is  filled  with 
distilled  water  at  the  commencement  of  the  experi- 
ment. The  third  tube  of  the  flask,  or  the  side  tube 
of  the  distillation  bulb,  is  fitted  by  means  of  an  air- 
tight stopper  almost  to  the  bottom  of  a  second  distil- 
lation-bulb. This  has  its  side  tube  suitably  bent,  and 
connected  with  a  Liebig's  potash  bulb  filled  with 
potassium  permanganate  solution  (3  per  cent)  contain- 
ing sodium  hydroxide  (about  1  gram).  The  gas 
delivery-tube  is  attached  to  the  potash  bulbs  and  dips 
below  the  mouth  of  the  measuring  vessel,  which  is  half 
filled  with  mercury  and  half  with  potassium  hydroxide 
(sp.  gr.  =  1.4).  The  air  is  displaced  from  the  appa- 
ratus by  a  slow  current  of  carbonic  anhydride,  which 
may  be  obtained  pure  and  free  from  air  by  dropping 
dilute  sulphuric  acid  (50  per  cent.  sp.  gr.  =  1.4)  into 
a  concentrated  solution  of  potassium  carbonate  (sp. 
gr.  =  1.45— 1.5). *  When  the  air  is  expelled  the  meas- 
uring tube  is  placed  in  position  and  a  slight  excess  of 
potassium  nitrite  solution  added  by  means  of  the 
dropping-funnel.  The  reaction  is  completed  by 
heating  on  the  water-bath  and  the  addition  of  a  little 
dilute  sulphuric  acid. 

(2)  Analysis  of  Salts  arid  Double  Salts. — The  prep- 

1  Fr.  Blau,  M.  13,  280. 


DETERMINATION   OF  THE   AMINO   GROUP,    ETC.      83 

aration  of  most  of  these  is  too  well  known  to  require 
comment.  Of  the  simple  salts  the  hydrocldorides  some  ■ 
times  can  only  be  induced  to  crystallize  in  a  state  of 
purity  by  the  action  of  anhydrous  hydrogen  chloride 
on  a  solution  of  the  base  in  ether  free  from  alcohol 
and  moisture.  The  chr ornate  and  pier at c,1  especially 
the  latter,  usually  crystallize  readily.  The  mercuri- 
cliloride,  RHgCl3 ,  has  occasionally  been  of  service  in 
cases  where  the  auro-cJiloride  or  platino-chloride  are 
oily  or  unstable  (cf.  pp.  89,  94). 

(3)  Acetylation. — This  is  described  in  the  next  sec- 
tion on  the  acetylation  of  the  aromatic  amines. 

(B)  Determination  of  Aromatic  Amino  Groups. 

The  following  methods  are  employed  for  the  deter- 
mination of  primary  aromatic  amines : 

(1)  Titration  of  the  salts. 

(2)  Preparation  of  diazo  derivatives. 

(a)  By  conversion  into  an  azo  dye. 

(b)  Indirect  method. 

(c)  Azoimide  method. 

(d)  By   means    of    the  Sandmeyer-Gattermann 

reaction. 

(3)  Analysis  of  salts  and  double  salts. 

(4)  Acetylation. 

(i)   TITRATION   OF   THE    SALTS.8 

(I)  Salts  of  aromatic  amines,  in  aqueous  or  alcoholic 
solution,    give  an   acid   reaction   with    rosolic   acid  or 

1  DelSpine,  Bull.  15,  53. 

2  Menschutkin,  B.  10,  316. 


84  RADICLES   IN   CARBON   COMPOUNDS. 

phenolphthalein.  The  salt,  preferably  the  hydro- 
chloride or  sulphate,  is  dissolved  in  water  or  dilute 
alcohol,  phenolphthalein  added,  and  the  titration 
carried  out  in  the  ordinary  manner  with  potassium 
hydroxide. 

(II)  Many  free  bases  may  be  directly  titrated  with 
hydrochloric  acid,  methyl  orange  being  used  as  an 
indicator. 

(2)    PREPARATION   OF   DIAZO-DERIVATIVES. 

{a)  Conversion  of  the  Base  into  an  Azo  Dye.1 

The  base,  for  example  aniline  (0.7-0.8  gram),  is 
dissolved  in  hydrochloric  acid  (3  cc)  and  diluted  with 
water  and  ice  to  100  cc.  A  titrated  solution  of  "  R- 
salt,"  sodium  2:3:6  naphtholdisulphonate,  is  pre- 
pared, of  such  strength  that  a  liter  is  equivalent  to  about 
10  grams  of  naphthol.  The  solution  of  the  hydro- 
chloride is  cooled  to  o°,  sodium  nitrite  added  in  quantity 
equivalent  to  the  aniline  or  other  base  present,  and 
the  mixture  gradually  poured  into  a  measured  quantity 
of  the  sulphonate  solution  which  has  been  treated 
with  sodium  carbonate  in  excess.  The  dye  produced 
is  precipitated  by  means  of  sodium  chloride,  filtered, 
and  the  filtrate  tested  with  diazobenzene  chloride  so- 
lution and  R-salt  to  determine  whether  the  latter  or 
the  base  is  in  excess.  By  repeating  the  experiment 
it  is  possible  to  find  the  volume  of  R-salt  solution 
necessary  to  combine  with  the  diazo-derivative  of  the 
base  originally  taken. 

1  Reverdin  and  De  la  Harpe,  Ch.  Ztg.  13,  I.  387,  407;  B.  22,  1004. 


DETERMINATION   OF   THE   AMINO   GROUP,   ETC.      85 

The  following  method  has  been  applied  to  aniline, 
ortho-  and  paratoluidine,  metaxylidine,  and  sulphanilic 
acid.1  A  known  quantity  of  the  base  is  diazotized 
and  made  made  up  to  a  certain  volume ;  it  is  then  im- 
mediately added  from  a  burette  to  a  solution  of 
"  Schafer's  salt,"  sodium  2  :  6-naphthol  sulphonate, 
of  known  strength,  which  has  been  mixed  with  sodium 
chloride  and  a  few  drops  of  ammonium  hydroxide, 
the  addition  being  continued  so  long  as  a  precipitate 
forms.  The  end  point  is  determined  by  bringing  a 
drop  of  the  clear  supernatant  liquor  on  to  filter  paper 
and  allowing  it  to  come  into  contact  with  a  drop  of 
the  diazo-solution.  The  progress  of  the  reaction  can  be 
followed  by  the  intensity  of  the  red  color  produced 
at  the  point  of  contact  of  the  two  liquids  on  the 
paper.  Towards  the  end  of  the  operation  the  color  is 
only  visible  in  the  middle  of  the  moist  circle.  In  the 
case  of  readily  soluble  dyes,  such  as  that  given  by 
sulphanilic  acid,  the  paper  must  be  covered  with  a 
thin  crust  of  sodium  chloride  and  the  test  portions 
allowed  to  fall  on  to  it;  more  sodium  chloride  must 
also  be  added  to  the  naphtholsulphonate  solution. 

(b)  Indirect  Method. 

This  is  extensively  employed  for  technical  purposes 
and  consists  of  an  inversion  of  a  method  for  the  de- 
termination of  nitrous  acid.2  The  base  is  treated  with 
three  times  its  weight  of  hydrochloric  acid  and  the 
mixture  dissolved  in  so  much  water  that  the  solution 

1  R.  Hirsch,  B.  24,  324. 

'A.  G.  Green  and  S.  Rideal,  Ch.  N.  49,  173. 


86  RADICLES   IN   CARBON   COMPOUNDS. 

contains  o.oi  to  o.  I  gram  equivalent  of  the  base. 
The  solution  is  maintained  at  o°  by  means  of  ice,  and 
titrated  with  sodium  nitrite  solution,  potassium  iodo- 
starch  paper  being  used  as  indicator ;  the  operation  is 
ended  when  a  drop  of  the  mixed  liquids  gives  a  blue 
coloration  with  the  paper.  The  nitrite  solution  should 
be  about  N/io.  It  is  prepared  '  by  dissolving  the  nitrite 
in  300  parts  of  cold  water  and  is  titrated  by  adding 
N/10  potassium  permanganate  solution  until  a  distinct 
permanent  red  coloration  is  obtained ;  two  or  three 
drops  of  dilute  sulphuric  acid  are  now  added,  then 
immediately  excess  of  the  permanganate,  the  liquid  is 
made  strongly  acid  with  sulphuric  acid,  heated  to 
boiling,  and  the  excess  of  permanganate  determined 
by  means  of  N/10  oxalic  acid  solution. 

(c)  Azoimide  Method.* 

This  is  specially  applicable  to  compounds  containing 
amino  groups  linked  to  different  nuclei.  The  azo- 
imides  are  prepared  by  the  action  of  ammonia  on  the 
diazoperbromides s  and,  on  account  of  the  large  con- 
tent of  nitrogen  in  the  former,  their  analysis  is  pecul- 
iarly well  adapted  for  the  determination  of  the  num- 
ber of  diazotisable  groups  in  the  molecule.  Details 
of  the  method  of  preparing  azoimides  have  been  given 
by  various  chemists4. 

1L.  P.  Kinnicutt  and  J.  U.  Nef,  Am.  Chem.  Journ.  5,  38S. 
Presenilis*  Zschr.  25,  223. 

2Meldola  and  Hawkins,  Ch.  N.  66,  33. 

•  Griess,  Ann.  137,  65. 

4Nolting,  Grandmougin,  and  O.  Michel,  B.  25,  3328.  Curtius 
and  Dedichen,  J.  pr.  [2],  50,  250. 


DETERMINATION  OF  THE  AMINO   GROUP,   ETC.      87 

(d)  Sandmeyer^-Gatternzanris*  Reaction. 

The  determination  of  the  amino  group  is  often 
conveniently  accomplished  by  converting  it  into  the 
diazo-derivative  and  replacing  the  nitrogen  by  chlo- 
rine; as  a  rule  the.  diazo-compound  is  not  isolated. 
The  following  example3  will  serve  to  illustrate  the 
method :  Metanitraniline  (4  grams)  and  concentrated 
hydrochloric  acid,  sp.  gr.  =  1.17  (7  grams),  are  dis- 
solved in  water  (100  grams),  and  10  per  cent  cuprous 
chloride  solution  (20  grams)  added ;  the  mixture  is 
heated  almost  to  boiling  in  a  reflux  apparatus,  and 
sodium  nitrite  (2.5  grams),  dissolved  in  water  (20 grams) 
is  gradually  run  in  by  means  of  a  dropping  funnel, 
the  mixture  being  well  shaken  during  the  addition. 
Nitrogen  is  evolved  and  a  heavy  brown  oil  collects 
which  solidifies  when  cooled  with  ice  and  is  purified 
by  distillation.  As  a  rule  these  chloro-derivatives  are 
volatile  with  steam ;  if  not  they  are  purified  by  means 
of  ether  or  benzene. 

The  above  method  is  the  one  originally  proposed 
by  Sandmeyer;  by  means  of  it  chloro-compounds  may 
be  readily  obtained  from  diamines  which  cannot  be 
diazotised  in  the  ordinary  manner.  The  cuprous 
chloride  employed  is  prepared  by  boiling  crystallized 
copper  sulphate  (25  parts)  and  anhydrous  sodium 
chloride  (12  parts)  with  water  (50  parts) ;  some  sodium 
sulphate  crystallizes  out,  and  when  the  reaction  is 
completed  the  product  is  mixed  with  concentrated 
hydrochloric    acid    (100   parts)   and   copper    turnings 

»B.  17,  1633.  »  IHd*  23,  1218.  *  Ibid.  11 ,  26$o. 


88  RADICLES   IN   CARBON   COMPOUNDS. 

(13  parts),  the  mouth  of  the  flask  is  loosely  closed 
and  the  mixture  boiled  until  the  liquid  becomes  color- 
less. Sufficient  concentrated  hydrochloric  acid  is  now 
added  to  bring  the  weight  of  the  mixture  to  203.6 
parts,  since  only  6.4  parts  of  the  copper  actually  dis- 
solve, 197  parts  of  solution  are  obtained  which  con- 
tains 0.2  gram  molecules  of  Cu.  CI.  The  filtered 
solution  may  be  retained  a  considerable  time  in  a  well 
closed  bottle  containing  carbonic  anhydride.1 

Cupric  chloride  is  reduced  to  cuprous  chloride  by 
hypophosphorus  acid,2  hence,  in  place  of  the  cuprous 
chloride  solution  prepared  according  to  the  foregoing 
method,  a  mixture  of  hydrochloric  acid,  copper  sul- 
phate solution,  and  sodium  hypophosphite  may  be 
employed.3 

The  use  of  finely  divided  copper  instead  of  cuprous 
chloride  has  been  suggested;4  amongst  other  advan- 
tages the  reaction  proceeds  at  the  ordinary  temperature, 
and  the  yield  is  frequently  improved.  The  copper  is 
prepared  by  adding  zinc-dust,  through  a  fine  sieve,  to 
a  cold  saturated  solution  of  copper  sulphate  until  only 
a  faint  blue  color  remains,  the  product  is  well  washed 
by  decantation  with  large  quantities  of  water,  the 
remaining  zinc  removed  by  digestion  with  highly  di- 
lute hydrochloric  acid,  and  the  copper  filtered  and 
washed  with  water  until  neutral ;  it  is  preserved  in  the 
form  of  a  paste  in  well-closed  bottles.  The  follow- 
ing example  will  illustrate  the  method  of  work- 
ing:  Aniline  (3.1  grams)  is  mixed  with  40  per  cent. 


1  Feitler,  J.  pr.  4,  68.  2  A.  Cavazzi,  Gazz.  16,  167. 

3  A.  Angeli,  Ibid.  21,  2,  258.  4  Gattcrmann,  B.  23,  1218. 


DETERMINATION   OF  THE   AMINO   GROUP,    ETC.      89 

hydrochloric  acid  (30  grams)  and  water  (15  cc),  the 
liquid  is  cooled  to  o°  and  a  saturated  aqueous  solution 
of  sodium  nitrite  (2.3  grams)  quickly  added,  the  liquid 
being  vigorously  stirred,  preferably  by  means  of  a 
turbine ;  the  reaction  is  completed  in  one  minute. 
Finely  divided  copper  (4  grams)  is  now  gradually 
added  to  the  diazo  solution,  which  is  well  stirred;  the 
reaction  requires  15-30  minutes  for  completion,  this 
is  signalized  by  the  particles  of  copper  ceasing  to  be 
carried  to  the  surface  of  the  liquid  by  the  escaping 
bubbles  of  nitrogen.  The  chlorobenzene  is  removed 
by  steam  distillation. 

(3)    ANALYSIS    OF    SALTS   AND    DOUBLE    SALTS. 

The  remarks  on  the  salts  of  aliphatic  amines  (p.  83) 
apply  generally  to  those  of  the  aromatic  series ;  the 
accumulation  of  negative  groups  in  their  molecules 
often  completely  prevents  the  formation  of  salts.  As 
a  rule  the  auro- chloride  contains  one  atom  of  gold  for 
each  amino  group,  and  the  p  latino -chloride  one  atom 
of  platinum  to  two  amino  groups,  but  amino  pyridine 
platino-chloride  has  the  formula  (CgHgN^.H^PtCle,,.1 
Sometimes  the  alkyl  haloid  salts  are  of  service,  but 
many  primary  bases  do  not  form  them.2  In  presence 
of  secondary  or  tertiary  amino  groups  the  method 
yields  fallacious  results.  Certain  compounds  free 
from  nitrogen  may  form  salts,  dimethylpyrone,  for 
example,  gives  amongst  others  a  platino-chloride 
(C,H.O,),.H,PtCI..' 

1  M.  15,  176.         s  Hofmann,  Jahresbericht  {1863),  p.  421. 
3  Collie  &  Tickle,  Journ.  Chem.  Soc.  75,  712. 


go  RADICLES   IN   CARBON   COMPOUNDS. 

(4)    ACETYLATION. 
The  methods  of  acetylation  described  for  the  deter- 
mination of  hydroxyl  (Chapter  I)  are  also  applicable 
to  the  amino  group  (cf.  acetylation  of  imides,  p.  92). 

DETERMINATION    OF    THE  N1TRILE  GROUP  (C:N.) 

The  nitrile  radicle  is  determined  by  hydrolysis,  the 
resulting  ammonia  or  acid  being  collected. 

(a)  Prolonged  boiling  with  hydrochloric  acid  is 
usually  sufficient  to  cause  hydrolysis;  the  product  is 
then  treated  with  alkali  in  excess,  and  the  ammonia 
distilled  off  and  determined  in  the  ordinary  manner. 

{b)  Should  the  hydrolysis  only  take  place  in  the 
presence  of  aqueous  or  alcoholic  alkali  an  apparatus 
similar  to  that  employed  in  Zeisel's  method  for  the 
determination  of  methoxyl  is  used  (Fig.  1,  p.  34). 
A  current  of  air,  freed  from  carbonic  anhydride,  ^is 
passed  through  the  apparatus,  and  the  bulbs  are  filled 
with  concentrated  alkali  solution ;  the  ammonia  is 
most  readily  determined  as  the  platino-chloride.  At 
the  conclusion  of  the  experiment  the  flask  A  will 
contain  the  alkali  salt  of  the  acid  produced,  and  may 
be  treated  by  one  of  the  methods  described  for  the 
determination  of  carboxyl  (Chapter  II). 

(c)  The  hydrolysis  of  nitriles  ]  may  be  hindered  by 
stereo-chemical  influences,  especially  in  the  case  of 
diortho-substituted  compounds,2  just  as  the  corre- 
sponding aeids  etherify  with  difficulty,  or  not  at  all, 
under  the  influence  of  hydrogen  chloride.    The  nitriles 

1  M.  and  J.,  II,  p.  545. 

s  A.  W.  v.  Hofmann,  B.  17,  1914;  18,  1825;  Stallburg,  Ann. 
278,  209.  Cain,  B.  28,  969.  V.  Meyer  and  Erb,  Ibid.  29,  834,  foot- 
note.    Sudborough,  Journ.  Chem.  Soc.  61,  601. 


DETERMINATION  OF  THE   AMINO    GROUP,   ETC.      9 1 

in  question,  although  they  resist  prolonged  heating  at 
a  high  temperature  in  a  sealed  tube  with  hydrochloric 
acid,  are  all  converted  into  amides  by  continued  boil- 
ing with  alcoholic  potassium  Hydroxide.1  The  amide 
is  hydrolysed  to  the  acid  in  the  manner  described  in 
the  following  section :  Cyanmesitylene a  requires  boil- 
ing during  seventy-two  hours  with  alcoholic  potassium 
hydroxide,  and  triphenylacetonitrile  3  needs  fifty  hours 
boiling  with  the  same  reagent  to  produce  the  amide. 
Some  nitriles  that  are  otherwise  resistant  may  be 
hydrolysed  by  heating  at  I20°-I30°  during  an  hour 
with  90  per  cent  sulphuric  acid  (20—30  parts).  The 
resulting  amide  is  converted  into  the  acid  by  means  of 
nitrous  acid4  (cf.  following  section).  Unhydroly sable 
nitriles  have  also  been  described.6 

{d)  Certain  amides  may  be  obtained  by  the  action 
of  alkaline  hydrogen  peroxide  at  4006  on  the  nitriles; 
the  resulting  compounds  are  then  treated  in  the 
manner  described  in  the  preceding  section. 

DETERMINATION  OF  THE  AMIDO  GROUP  (CO  .  NH2). 

The  amido  group  is  determined  by  hydrolysis,  in  a 
similar  manner  to  the  nitrile  group  (preceding  sec- 
tion). The  method  employed  for  the  hydrolysis  of 
very  stable  amides7  is  best  illustrated  by  its  applica- 
tion to  the  preparation  of  triphenylacetic  acid."     The 

1  Bouveault.  S.  p.  80.     Hantzsch  and  Lucas,  B.  28,  748. 

1  V.  Meyer  and  Erb,  Ibid.  29,  834.     3  V.  Meyer,  Ibid.  28,  2782. 

4  Sudborough,  Jour.  Chem.  Soc.  67,  601.     Munch,  B.  29,  64. 

5  Radziszewski,  Ibid.  18,  355. 

6  Claus  and  Wallbaum    J.  pr.  56,  52. 
T  Bouveault,  Bull.  [3],  9,  370. 

8  G.  Heyl  and  V.  Meyer,  B.  28,  2783. 


92  RADICLES   IN    CARBON   COMPOUNDS. 

finely  divided  amide  (0.2  gram)  is  gently  warmed 
with  concentrated  sulphuric  acid  (1  gram)  and  the 
clear  solution  cooled  in  ice,  sodium  nitrite  (0.2  gram), 
dissolved  in  water  (1  *gram)  cooled  to  o°  is  added 
very  slowly  by  means  of  a  capillary  tube ;  when  the 
addition  is  complete  the  test-tube  containing  the 
mixture  is  placed  in  a  beaker  of  water  and  gradually 
heated.  The  evolution  of  nitrogen  commences  at 
6o°-70°,  and  is  completed  at  8o°-90° ;  finally  the  tube 
is  heated  in  boiling  water  for  3-4  minutes,  but  not 
longer.  When  cool,  ice  is  added  to  the  liquid,  the 
precipitated  solid  collected,  and  purified  by  solution  in 
dilute  sodium  hydroxide  and  precipitation  with  sul- 
phuric acid.  It  is  highly  desirable  to  use  the  exact 
theoretical  quantity  of  sodium  nitrite  dissolved  in  the 
smallest  possible  volume  of  water.1  Stereo-chemical 
influences  are  effective  in  hindering  the  hydrolysis  of 
amides  as  they  are  that  of  the  nitriles.2 

DETERMINATION  OF  THE  IMIDE  GROUP  (NH). 
The  following  methods  are  employed  for  the  deter- 
mination of  the  imide  group : 

(1)  Acetylation. 

(2)  Alkylation. 

(3)  Analysis  of  salts. 

(4)  Elimination  of  the  imidogen  as  ammonia. 

(i)   ACETYLATION    OF   IMIDES  (SECONDARY  AMINES). 

Imides  may  be  acetylated  by  any  of  the  methods 
employed  for  the  determination  of  hydroxyl  which  are 

1  Sudborough,  Jour.  Chem.  Soc.  67,  604. 

8  A  bibliography  of  the  subject  is  given  in  M.  and  J.  II,  p.  545- 


DETERMINATION   OF  THE   AMINO    GROUP,    ETC.      93 

described  in  Chapter  I.  The  reaction  usually  takes 
place  without  difficulty,  and  therefore  an  indirect 
method1  may  be  utilized.  A  weighed  quantity  of  the 
compound  (about  1  gram)  is  placed  in  a  flask,  fitted  to 
a  reflux  apparatus,  and  acetic  anhydride  (about  2 
grams)  quickly  added.  The  anhydride  should  be 
added  from  a  suitably  stoppered  vessel,  which  is 
weighed  before  and  after  the  addition.  The  mixture 
is  allowed  to  remain  at  the  ordinary  temperature  during 
about  thirty  minutes,  water  (50  cc)  is  then  added,  and 
the  liquid  heated  on  the  water-bath  during  forty-five 
minutes  ;  the  solution  is  now  cooled,  diluted  to  a  definite 
volume,  and  titrated  with  sodium  hydroxide  of  known 
strength,  phenolphthalein  being  used  as  indicator. 

The  process  was  specially  worked  out  for 
methylaniline,  hence,  for  other  imides,  the  duration 
of  the  heating  and  the  temperature  require  modifica- 
tion according  to  the  readiness  with  which  they  react. 
It  may  be  desirable  to  heat  in  a  sealed  tube,  or  in  a 
dry  closed  flask,  the  mixture  being  constantly  shaken, 
and  the  anhydride  diluted  with  ten  volumes  of 
dimethylaniline.3 

(2)  ALKYLATION  OF  IMIDES. 
Some  imide  groups  may  be  methylated  by  dissolv- 
ing the  compound  in  alkali  and  gradually  adding 
methylic  iodide;  the  mixture  is  constantly  shaken  and 
maintained  at  the  ordinary  temperature.  The  method 
has  been  extensively  employed  in  the  investiga- 
tion of  purin  and  uric  acid  derivatives.3 

1  Reverdin  and  De  la  Harpe,  B.  22,  1005. 

2  H.  Giraud,  Bull.  (3),  II.  142. 

3  E.  Fischer,  B.  28,  2479;  30,  569,  3094;  32,  453.  C.  (1897),  II.  157. 


94 


RADICLES   IN   CARBON   COMPOUNDS. 


(3)    ANALYSIS    OF    SALTS. 

The  remarks  on  the  analysis  of  salts  of  primary 
amines  (pp.  83,  89)  apply  equally  to  those  of  second- 
ary ones. 

(4)    ELIMINATION    OF   IMIDOGEN   AS   AMMONIA. 

The  hydrolysis  of  the  imides  is  usually  carried  out 
by  prolonged  boiling  with  hydrochloric  acid  either  in 
an  open  vessel  or  under  pressure  in  a  sealed  tube. 
The  liquid  is  then  made  alkaline,  the  ammonia  or 
amine  volatilized  into  hydrochloric  acid,  and  the  excess 
of  the  latter  determined  by  titration  or,  in  some  cases, 
by  means  of  the  platino-chloride. 

DETERMINATION  OF  METHYL  IMIDE  (NCH3).1 

The  hydriodides  of  methylated  bases  eliminate 
methyl  iodide  at  2OO0-3OO°  in  accordance  with  the 
equation  RaNCH,.HI  ^  RaNH  +  CHSI ;  the  iodide 
may  be  determined  by  Zeisel's  method  (cf.  p.  33). 
The  apparatus  employed  is  iden- 
tical with  that  of  Zeisel  except 
the  vessel  in  which  the  sub- 
stance is  heated.  This  is  shown 
?2  in  Fig.  10,  and  consists  of  a 
double  flask  a  b  connected 
by  means  of  a  cork  with  the 
vessel  c.  The  method  is  modi- 
fied according  to  whether  one 
or  more  alkyl  groups  are  linked 
to  nitrogen,  and,  in  the  latter 
case,  whether  these  are  to  be 


1  J.  Herzig  and  H.  Meyer,  B.  27,  319.   M.  15,  613;  16,  599. 


DETERMINATION  OF  THE  AMINO   GROUP,   ETC.      95 

determined  successively;  finally  the  presence  of  alky- 
loxy  groups,  in  addition  to  methyl  imide,  demands 
special  manipulation. 

(1)  Determination  with  only  one  Alky  I  linked  to 
Nitrogen. 

The  compound  (o.  15-0.3  gram)  as  free  base, 
nitrate,  or  haloid  salt  is  placed  in  the  flask  a  together 
with  sufficient  hydriodic  acid  (sp.  gr.  =  1. 68-1. 72)  to 
fill  the  vessel  c  to  the  mark  de ;  the  object  of  this  is  to 
retain  any  volatile  basic  compounds  which  might  be 
carried  over  by  the  carbonic  anhydride.  In  addition 
to  the  acid  the  flask  a  also  contains  ammonium  iodide 
in  quantity  equal  to  5-6  times  that  of  the  substance 
employed.  The  vessel  C  is  connected  directly  with 
the  condenser  (Fig.  1,  p.  34);  it  should  contain  a  little 
red  phosphorus  if  much  iodine  is  liberated  in  a,  as  is 
usually  the  case  when  nitrates  are  employed.  The 
flask  b  is  filled  with  asbestos,  a  little  of  which  is  also 
placed  in  a  to  facilitate  the  boiling.  A  more  rapid 
current  of  carbonic  anhydride  is  used  than  in  the  de- 
termination of  methoxyl,  so  as  to  remove  the  methyl 
iodide  as  quickly  as  possible  and  prevent  its  entering 
into  combination  with  the  other  compounds  produced, 
consequently  two  absorption  flasks  with  silver  nitrate 
must  always  be  employed.  The  heating  is  done  by 
means  of  a  sand-bath  of  copper  with  a  sheet-iron  bot- 
tom ;  it  is  divided  into  two  equal  portions  by  a  partition, 
and  is  of  such  a  shape  as  to  permit  the  flasks  being 
immersed  in  the  sand  up  to  the  \\r\Q  fg.  The  flask  a 
is  first  heated,  carbonic  anhydride  being  passed  through 


g6  RADICLES   IN   CARBON  COMPOUNDS. 

the  apparatus,  a  portion  of  the  acid  distils  into  b  and 
some  into  c.  Gradually  the  second  chamber  of  the 
bath  is  filled  with  sand,  and  b  then  directly  heated. 
All  the  acid  soon  accumulates  in  c,  the  carbonic  an- 
hydride bubbling  through  it  whilst  the  flask  a  contains 
only  the  hydriodide  of  the  base.  The  commencement 
of  the  decomposition  is  indicated  by  a  turbidity  in  the 
silver  nitrate  solution,  and  it  occurs  soon  after  the 
acid  has  been  expelled  from  the  flask  b.  The  remain- 
der of  the  experiment  is  carried  out  exactly  as  in  the 
methoxyl  determination. 

(2)  Determination  with  two  or  more  Alky  I  Groups 
linked  to  Nitrogen. 

This  is  carried  out  in  the  manner  described  in  the 
preceding  section ;  when  the  operation  is  completed 
the  appararus  is  allowed  to  cool  in  a  current  of  car- 
bonic anhydride,  c  is  detached  from  the  condenser, 
and  by  cautious  tilting  the  acid  poured  from  it  back 
to  b,  whence  it  will  pass  spontaneously  to  a.  A  fresh 
quantity  of  silver  nitrate  is  placed  in  the  absorption 
flasks,  and  the  apparatus  is  ready  to  heat  again.  The 
operation  is  repeated  until  the  quantity  of  silver  iodide 
obtained  is  equivalent  to  an  amount  of  alkyl  weighing 
less  than  0.5  per  cent  of  the  substance  employed. 
It  is  important  to  conduct  the  determinations  at  the 
lowest  possible  temperature,  and  therefore  a  thermom- 
eter is  placed  in  the  sand-bath  which  is  never 
allowed  to  exceed,  by  more  than  40°,  the  temperature 
(200°-2  50°)  at  which  the  silver  nitrate  solution  first 
becomes  turbid.      When  several  alkyl  groups  are  pres- 


DETERMINATION  OF  THE  AMINO  GROUP,  ETC.   97 


ent,  it  is  advisable  to  use  more  ammonium  iodide 
than  otherwise,  about  5  grams  in  a,  and  2-3  grams  in 
b.  Each  decomposition  requires  some  two  hours  for 
completion,  and  three  such  are  amply  sufficient  even 
though  the  compound  contains  three  or  four  alkyls. 

(3)  Successive  Determination  of  the  Alky  I  Groups. 

The  alkyl  groups  may  be  successively  eliminated 
from  feebly  basic  compounds  such  as 
caffeine  or  theobromine.  In  place  of 
the  vessel  previously  employed  (Fig. 
10),  the  substance  is  heated  in  one 
of  the  shape  shown  in  Fig.  II,  It  is 
immersed  in  a  sand-bath  to  the  mark 
ab ;  after  heating  the  acid  is  allowed 
to  flow  back  to  the  flask,  a  little  am- 
monium iodide  is  added,  and  the 
heating  repeated, — the  operation  be- 
ing performed  a  third  time,  with  the 
addition  of  more  ammonium  iodide, 
if  three  alkyl  groups  are  present. 


Fig.  11. 


(4)  Determination    of  MetJiyl  Imide    in    Presence    of 
Methoxyl. 

The  methyl  imide  maybe  determined  in  presence  of 
methoxyl  by  heating  the  hydriodide  alone  in  the  flask 
a  (Fig.  10);  it  is,  however,  preferable  to  add  to  it 
hydriodic  acid  (10  cc),  and  heat  the  flask  in  an  oil-  or 
glycerol-bath  so  that  scarcely  any  distils  over  into  b. 
When  the  operation  is  ended,  which  is  indicated  by 
the  silver  nitrate  solution  becoming  clear,  the  tem- 
perature is  raised,  and  the  acid  distilled  off  until  only 


98  RADICLES  IN   CARBON  COMPOUNDS. 

so  much  remains  in  a  as  is  usually  employed  for  the 
methyl  imide  determination  (see  section  i).  During 
the  distillation  the  silver  nitrate  solution  remains  quite 
clear,  and  the  methoxyl  determination  is  completed. 
A  fresh  portion  of  silver  nitrate  is  taken,  the  excess  of 
acid  removed  from  b  and  c,  ammonium  iodide  added, 
and  the  methyl  imide  determination  commenced  in 
the  manner  described  in  the  preceding  sections. 

(5)   General  Remarks  on  the  Method. 

The  purity  of  the  hydriodic  acid  and  ammonium 
iodide  must  be  ascertained  by  means  of  a  blank  ex- 
periment. 

The  method  is  applicable  to  all  compounds  which 
can  form  a  hydriodide  even  though  this  may  not  be 
capable  of  isolation,  and  accurate  results  are  obtained 
by  the  use  of  the  hydrobromide,  hydrochloride,  or 
nitrate.  Quantitative  results  are  also  obtained  in  the 
case  of  many  compounds,  such  as  ;z-ethylpyrroline, 
methylcarbazole,  and  dimethylparabanic  acid,  which  do 
not  form  salts.  The  limits  of  error  lie  between  -f-  3 
and  —  15  per  cent  of  the  total  alkyl,  consequently  the 
presence  or  absence  of  one  such  group  can  only  be 
determined  with  certainty  when  the  theoretical  dif- 
ference in  composition  for  one  alkyl  exceeds  2  per 
cent,  or,  in  other  words,  when  the  molecular  weight 
of  the  original  methylated  compound  is  less  than  650. 

In  considering  the  results  obtained  it  is  necessary  to 
observe  the  color  of  the  silver  iodide;  should  this  be 
dark  or  gray  instead  of  yellow,  the  error  is  almost 
always  positive. 

100  parts  Agl  =  6.38  parts  of  CH3. 


DETERMINATION   OF  THE   AMINO    GROUP,    ETC.      99 

DETERMINATION  OF  ETHYL  IMIDE  (NC2H6). 

The  method  '  of  determination  is  exactly  the  same 
as  that  described  above  for  methyl  imide.  100  parts 
Ag  I  =  12.34  parts  of  CaH5. 

DIFFERENTIATION    OF  THE    METHYL    IMIDE    AND 
ETHYL  IMIDE  GROUPS. 

The  method  of  determination  by  means  of  the  alkyl 
iodides  does  not,  as  a  rule,  distinguish  between  ethyl 
imide  and  methyl  imide;  in  doubtful  cases  it  is 
necessary  to  distil  a  considerable  quantity  of  the 
hydriodide  of  the  base,  and  purify  and  identify  the 
alkyl  iodide  which  is  evolved.  A  second  method 
consists  in  distilling  the  base  with  potassium  hy- 
droxide, evaporating  the  distillate  with  hydrochloric 
acid  to  dryness,  separating  the  organic  hydrochlorides 
from  ammonium  chloride  by  means  of  absolute 
alcohol,  and  converting  the  former  into  picrates, 
platinochlorides,  etc.,  which  may  then  be  identified; 
the  method  must,  however,  be  used  with  cantion,  as 
it  may  lead  to  erroneous  results. 

1  J.  Herzig  and  H.  Meyer,  B.  27,  319.     M.  15,  613  ;  16,  599. 
'Ciamician  and  Boeris,  B.  29,  2474. 


Chapter  V. 

DETERMINATION  OF  THE  DIAZO  GROUP  (R.N.N.  R); 
OF  THE  HYDRAZIDE  RADICLE  (NH  .  NH2);  OF  THE 
NITRO-GROUP  (NO,);  OF  THE  IODOSO-GROUP  (10); 
OF  THE  IODOXY-GROUP  (IOa);  OF  THE  PEROXIDE 
GROUP  £/?;   IODINE  NUMBER. 

\o 

DETERMINATION  OF  THE  DIAZO  GROUP  (R .  N  :  N  .  R). 

The  aliphatic  and  aromatic  diazo-compounds  are 
differently  constituted,  hence  the  methods  adapted  for 
their  determination  are  not  identical. 

(A)   Aliphatic   Diazo-compounds   (c  —  CH<^  n  ). 

The  following  methods  are  employed:1 
(i)    Titration  with  iodine. 

(2)  Analysis  of  the  iodo-derivatives. 

(3)  Determination  of  the  nitrogen  in  the  wet  way. 

(i)    DETERMINATION    OF    THE    NITROGEN     BY    TITRA- 
TION   WITH    IODINE. 

This  reaction  takes  place  in  accordance  with  the 
equation  CHNa  .  COOR  +  I,  »->  CHI, .  COOR  +  N,. 

Rather  more  than  the  theoretical  quantity  of  iodine 
is  accurately  weighed,  dissolved  in  absolute  ether,  and 
added,  by  means  of  a  burette,  to  a  known   quantity 

1  Curtius,  J.  pr.  146,  422. 

100 


DETERMINATION   OF  THE   DlAZO   GROUP,    ETC.    IOI 

of  the  diazo-compound  also  in  ethereal  solution;  the 
end  of  the  reaction  is  indicated  by  a  sharp  change  in 
the  color  of  the  diazo-compound  from  lemon  yellow 
to  red;  towards  the  conclusion  of  the  titration  the 
reaction  is  facilitated  by  warming  the  liquid  on  the 
water-bath.  The  excess  of  iodine  solution  is  run  into 
a  tared  flask,  the  ether  cautiously  removed,  and  the 
residue  weighed.  Unless  the  compound  employed  is 
in  a  high  state  of  purity  the  change  of  color  in  the 
liquid  takes  place  long  before  all  the  nitrogen  has 
been  expelled. 

(2)    ANALYSIS    OF   THE    IODINE    DERIVATIVE. 

The  iodine  in  the  iodo-compound  may  be  deter- 
mined in  the  ordinary  manner,  or  the  following  simpler 
method,  first  used  in  the  investigation  of  diazoaceta- 
mide,1  may  be  employed.  A  weighed  quantity  of 
the  substance  is  placed  in  a  tared  beaker,  dissolved 
in  a  little  absolute  alcohol,  and  iodine  added  until  a 
permanent  red  coloration  is  obtained.  The  alcohol 
is  volatilized  on  the  water-bath,  the  excess  of  iodine 
removed  by  cautious  heating,  and  the  crystalline 
residue  weighed.  In  this  case  also  the  compound 
employed  must  be  pure. 

(3)    DETERMINATION    OF   THE    NITROGEN    IN    THE 
WET  WAY. 

On  account  of  the  great  volatility  of  the  aliphatic 
ethereal    diazocarboxylates    the    method    of   nitrogen 

1  Curtius,  J.  pr,  146,  423. 


102 


RADICLES   IN   CARBON   COMPOUNDS. 


Fig.  12. 


determination  described  on  p.  81  cannot  be  employed. 
This  difficulty  is  overcome  *  by  the  use  of  the  apparatus 
„  shown  in  Fig.  12.     A  is  a 

large  gas  cylinder  contain- 
ing water,  r  a  capillary  tube, 
the  upper  open  end  of 
which  rises  a  little  above 
the  level  of  the  water  in 
A.  E  is  a  gas  measuring 
tube,  B  a  small  condenser 
fitted  to  the  little  flask  C 
by  means  of  a  rubber  stop- 
per; through  this  a  platinum  wire  also  passes.  It  is 
bent  in  the  manner  shown  and  carries  a  glass-stoppered 
vessel  such  as  is  employed  in  vapor  density  deter- 
minations. The  flask  C  is  partially  filled  with  well 
boiled,  highly  dilute  sulphuric  acid,  the  compound 
(about  0.2  gram)  weighed  into  the  small  vessel  s,  and 
the  apparatus  fitted  together  air-tight.  When  the  air 
in  the  apparatus  is  in  equilibrium  with  the  atmosphere, 
which  can  readily  be  observed  if  a  drop  of  water  is 
placed  in  r,  the  volume  of  air  in  the  eudiometer  tube 
is  read  off,  and  the  temperature  noted.  The  vessel  s 
is  now  dropped  into  the  acid,  which  is  gradually  heated 
to  boiling;  the  decomposition  is  completed  in  a  few 
minutes.  The  apparatus  is  allowed  to  cool  com- 
pletely, the  level  of  water  in  and  outside  the  tube  E 
adjusted,  and  the  volume,  temperature,  and  pressure 
noted ;  the  difference  in  volume  from  the  previous 
reading  gives  the  quantity  of  nitrogen  evolved.     As  a 


1  Curtius,  J.  pr.  146,  417. 


DETERMINATION   OF   THE   DIAZO   GROUP,    ETC.     IOJ 

rule  the  pressure  does  not  materially  change  during 
the  experiment. 

Compounds  containing  an  amino  as  well  as  a  diazo- 
group,  such  as  diazoacetamide,  may  be  decomposed 
by  means  of  dilute  hydrochloric  acid  ;  after  the  evolu- 
tion of  nitrogen  is  completed  the  ammonium  chloride 
in  the  flask  c  may  be  precipitated  with  platinum 
chloride  and  the  amido  and  diazo  nitrogen  thus  sepa- 
rately determined  in  one  operation. 

(B)  Aromatic  Diazo  Compounds.    (Diazonium 

Derivatives    C.N.  OH) 

in 
N 

The  diazo  group  in  aromatic  compounds  is  usually 
determined  by  the  preceding  method  '  (3),  but  it  is 
preferable  to  employ  a  Lunge's  nitrometer  and  40  per 
cent  sulphuric  acid.2  If  the  compound  is  unstable 
and  the  determination  is  made  in  a  current  of  carbonic 
anhydride  3  the  air  should  be  expelled  at  a  temperature 
of  00.4  Sulphuric  acid,  sp.  gr.  =  1.306,  has  a  vapor 
tension  of  9.4  mm  at  15 


o  t> 


DETERMINATION  OF  THE  HYDRAZIDE  GROUP 

(NH.NH2). 

Either  the  oxidation  or  iodometric  method  may  be 
employed. 


1  Knoevenagel,  B.  23,  2997.  v.  Pechmann  and  Frobenius,  Ibid. 
27,  706. 

1  Bamberger,  Ibid.  27,  2598. 

3  H.  Goldschmidt  and  A.  Merz,  Ibid,  29,  1369;  30,  671. 

4  Hantzsch,  Ibid.  28,  1741.  6  Regnault. 


104  RADICLES   IN   CARBON   COMPOUNDS. 

(i)    OXIDATION    OF    HYDRAZIDES.1 

Boiling  Fehling's  solution  hydrolyses  acid  hydra- 
zides,  and  oxidizes  the  resulting  phenyl  hydrazine,  the 
nitrogen  of  which  is  evolved  quantitatively  and  deter- 
mined by  the  method  described  on  p.  65.  The  com- 
pound is  dissolved  if  possible  in  water  or  alcohol ; 
hydrazides  which  do  not  dissolve  are  weighed  into  a 
small  stoppered  vessel  which  is  fixed  mouth  down- 
wards in  the  hole  of  the  stopper  otherwise  occupied  by 
the  funnel  A,  Fig.  8,  and  is  dropped  into  the  boiling 
solution  by  means  of  a  glass  rod  of  the  same  volume. 
Insoluble  compounds  may  also  be  treated  according 
to  the  following  method:3  100  cc  Fehling's  solution 
and  150  cc  alcohol,  together  with  a  few  fragments  of 
porcelain,  are  placed  in  a  500  cc  flask  fitted  with  a 
doubly  bored  rubber  stopper.  In  the  one  hole  the 
tube  containing  the  weighed  substance  is  placed, 
whilst  through  the  other  passes  the  end  of  an 
inclined  condenser.  The  contents  of  the  flask  are 
boiled  and  the  open  end  of  the  condenser  connected 
with  a  bent  tube  terminating  in  a  short  leg  which 
dips  below  water.  When  no  more  air  is  expelled  a 
measuring  vessel  full  of  water  is  placed  over  the 
end  of  the  tube,  and  the  vessel  with  the  substance 
pressed  into  the  flask  by  means  of  a  rod.  Continued 
boiling  for  a  short  time  suffices  to  liberate  all  the 
nitrogen. 

1  H.  Strache  and  S.  Iritzer,  M.  14,  37.  Holleman  and  de  Vries, 
Rec.  10,  229.  De  Vries,  B.  27,  1521;  28,  2611.  Petersen,  Z.  An. 
5,  2. 

8  H.  Meyer,  M.  18,  404. 


DETERMINATION   OF  THE   DIAZO   GROUP,    ETC.     105 

In  some  cases  it  is  desirable  to  recover  the  acid 
on  account  of  its  rarity,  or  to  remove  it  in  order  to 
facilitate  the  determination,  as  in  the  case  of  stearic 
acid,  the  potassium  salt  of  which  causes  the  liquid  to 
froth  over.  This  can  be  accomplished,  if  the  acid  is 
sparingly  soluble  in  water  or  dilute  hydrochloric  acid, 
by  boiling  the  hydrazide  with  concentrated  hydro- 
chloric acid,  during  several  hours;  the  solution  is  made 
up  to  100  cc,  the  organic  acid  removed  by  means  of 
a  dry  filter,  the  first  few  drops  of  the  filtrate  rejected, 
and  50  cc  of  the  remainder  taken  for  the  determination. 
This  method  of  hydrolysis  does  not  distinguish 
between  hydrazides  and  hydrazones,  as  the  latter  are 
also  acted  upon  by  hydrochloric  acid.  Ortho-  and 
paratolylhydrazides  are  oxidized  in  the  same  manner 
as  phenylhydrazides,  so  that  the  method  is  also  ap- 
plicable to  them.1 

Platinic  chloride  oxidizes  hydrazine  hydrochloride 
in  accordance  with  the  equation : 

NaH4.2HCl  +  2PtCl4  *->  Na  +  6HC1  +  2PtCl, ; 

the  evolved  nitrogen    is   determined   by   the  method 
described  on  p.  101.2 

Hydrazine  salts  may  be  titrated  by  potassium  per- 
manganate in  presence  of  sulphuric  acid,  provided  the 
concentration  of  the  latter  is  6-12  per  cent.1  The  re- 
action is  represented  by  the  equation 

i;N2H4  +  13O  m*  i3HuO  +  i4NHs  +  ioN,. 


1  M.  14,  38.  2  Curtius,  J.  pr.  147,  37. 

3  Petersen,  Z.  An.  5,  3. 


106  RADICALS   IN   CARBON   COMPOUNDS. 

(2)    IODOMETRIC    METHOD.1 

Phenylhydrazine  and  iodine  react  in  accordance  with 
the  following  equation : 

C6HBNH.NHa  +  2 1,  ^  3HI  +  N2  +  G.H.I. 

The  interaction  is  quantitative  in  highly  dilute  solu- 
tion with  iodine  present  in  excess.  The  determination 
is  made  by  adding  to  a  known  volume  of  N/10  iodine 
solution  the  highly  dilute  solution  of  the  base  or  its 
hydrochloride,  obtained  by  hydrolysis  as  described  in 
the  preceding  section ;  the  excess  of  iodine  is  then 
titrated  in  the  ordinary  manner. 

In  presence  of  dilute  sulphuric  acid  iodic  acid  oxi- 
dizes phenylhydrazine  and  this  reaction  may  also  be 
employed  for  the  determination.  The  strength  of  the 
iodic  acid  solution  is  ascertained  by  means  of  sul- 
phurous acid  of  known  titre;  it  is  then  added,  in 
excess,  to  the  highly  dilute  solution  of  phenyl- 
hydrazine  and  sulphuric  acid,  and  the  mixture  again 
titrated. 

To  the  above  methods  may  be  added  the  titration 
of  phenylhydrazine  with  hydrochloric  acid ;  methyl- 
orange  is  used  as  indicator,  and  tolerably  accurate 
results  are  obtained.8 

DETERMINATION   OF   THE   NITRO-GROUP  (NOa). 

(A)  Titration  Method.3 

Organic  nitro-compounds  are  reduced  to  amino- 
derivatives   by   the    action    of    stannous    chloride,    in 

1  E.  v.  Meyer,  J.  pr.  149,  115.  8  Strache  and  Iritzer. 

3  H.  Limpricht,  B.  11,  35. 


DETERMINATION  OF  THE   DIAZO   GROUP,    ETC.    107 

presence  of  hydrochloric  acid,  in  accordance  with  the 
equation 

R.NO,  +  3SnCl2  +  6HC1  »->  R.NH,  +  3SnCl4 
+  2H,0; 

the  unchanged  stannous  chloride  is  determined  by 
titration,  and,  from  the  quantity  which  has  reacted, 
the  number  of  nitro-groups  in  the  original  compound 
may  be  ascertained,  Solution  of  iodine,  or  of  potas- 
sium permanganate,  is  employed  for  the  titration.1 

Reagents  Required. 

(1)  Stannous  Chloride  Solution.  Tin  (150  grams) 
is  dissolved  in  concentrated  hydrochloric  acid,  the 
clear  liquid  decanted,  mixed  with  concentrated  hydro- 
chloric acid  (50  cc),  and  diluted  to  I  liter. 

(2)  odium  Carbonate  Solution.  Anhydrous  sodium 
carbonate  (180  grams)  and  sodium  potassium  tartrate 
(240  grams)  are  dissolved  in  water  and  diluted  to  I 
liter. 

(3)  Iodine  Solution.  Iodine  (12.54  grams)  is  dis- 
solved in  potassium  iodide  solution  and  the  liquid 
made  up  to  1  liter,  it  will  then  be  approximately  N/10, 
if  exactly  so  1  cc  =  0.0059  gram  Sn  =  0.000  655  gram 
NOa. 

(4)  Starch  Solution.  This  must  be  dilute,  recently 
prepared,  and  filtered. 

Potassium    Permanganate   Solution.      It    should    be 


1  Jenssen,  J.   pr.  78,   193.      S.  W.  Young  and  R.   E.  Svvain,  J. 
Am.  (1897),  19,  812-814.  Journ.  Chem.  Soc.  (1898),  74,  ii,  186. 


I08  RADICALS   IN    CARBON   COMPOUNDS. 

N/io,    and  may   be   used   instead   of   the   iodine,    its 
strength  being  determined  by  means  of  iron. 

(I)  Method  of  Determination  for  Non-volatile 

Compounds. 

After  the  titre  of  the  stannous  chloride  has  been 
ascertained,  the  nitro-compound  (about  0.2  gram)  is 
placed  in  a  100  cc  glass-stoppered  flask,  stannous  chlo- 
ride solution  (10  cc)  added,  and  the  liquid  warmed 
during  thirty  minutes.  When  cool,  the  mixture  is 
diluted  to  the  mark,  and,  after  shaking,  10  cc  trans- 
ferred to  a  beaker  by  means  of  a  pipette  ;  a  little  water 
is  added,  then  the  sodium  carbonate  solution,  until  the 
precipitate  which  first  forms  is  wholly  dissolved  ;  after 
the  addition  of  a  little  starch  the  iodine  solution  is  run 
in  until  a  permanent  blue  coloration  is  produced. 

The  results  of  the  analysis  are  calculated  according 
to  the  formula  N02  =  (a  —  £). 0.000765  5  gram, 
where  a  =  the  number  of  cc  of  iodine  solution  equiv- 
alent to  1  cc  of  the  stannous  chloride  solution,  and  b  = 
the  number  of  cc  of  iodine  solution  required  in  the 
determination. 

If  it  is  desired  to  use  the  potassium  permanganate 
10  cc  of  the  acid  liquid,  withdrawn  as  described  above, 
is  boiled  with  ferric  chloride,  and  the  ferrous  chloride 
produced  is  determined  in  the  ordinary  manner. 

(II)  Modified  MetJiod for  Volatile  Compounds. 

Volatile  nitro-compounds  are  weighed  in  a  test-tube 
about  30  cm  by  8  mm,  closed  with  a  cork ;  the  cork  is 
removed,   and  the  tube,   together  with  the   stannous 


DETERMINATION   OF   THE   DIAZO   GROUP,   ETC.    IO9 

chloride,  placed  in  a  second  larger  one,  20  cm  by  13- 
15  mm,  which  is  then  sealed.  The  larger  tube  may 
be  of  thin-wallcd,  readily  fusible  glass,  as  it  will  only 
be  subjected  to  a  very  slight  pressure.  The  tube  is 
heated  in  the  water-bath  during  1-2  hours,  and  well 
shaken  occasionally;  it  is  then  cooled,  the  contents 
completely  washed  into  a  100-cc  graduated  flask,  and 
treated  in  the  manner  described  in  the  preceding  sec- 
tion. The  use  of  a  sealed  tube  is  sometimes  advisable 
in  the  case  of  non-volatile  compounds  with  which  low 
results  may  be  obtained  by  heating  in  the  stoppered 
bottle. 

(B)  Diazo  Method.1 

Should  the  preceding  method  fail  to  give  decisive 
results  the  nitro-compound  must  be  reduced  to  the 
amino-derivative  and  this  treated  in  the  manner  de- 
scribed on  p.  87.  As  an  example  metanitrobenz- 
aldehyde  may  be  converted  into  metachlorobenzalde- 
hyde  at  one  operation.8  It  is  dissolved  in  concentrated 
hydrochloric  acid  (6  parts),  stannous  chloride  (4.5 
parts)  added,  and  after  the  reduction,  without  pre- 
cipitating the  tin,  it  is  mixed  with  the  calculated 
quantity  of  sodium  nitrite  and  an  equal  weight  of 
finely  divided  copper. 

DETERMINATION  OF  THE  IODOSO-  (IO)  AND 
IODOXY-  (IOa)  GROUPS. 

Iodoso-  and  iodoxy-compounds  in  presence  of 
glacial  acetic,  of  hydrochloric  acid,  or  of  dilute  sul- 
phuric acid  liberate  from  potassium  iodide  an  amount 

1  Gattermann,  B.  23,  1222.  8  Gattermann,  loc.  cit. 


110  RADICALS   IN   CARBON   COMPOUNDS. 

of  iodine  equivalent  to  their  content  of  oxygen  ;  one 
molecule  of  the  former  therefore  liberates  two,  and  of 
the  latter  four  atoms  of  iodine.  For  the  determina- 
tion the  substance  is  heated  on  the  water-bath  during 
four  hours  with  acidified  potassium  iodide  solution  in 
a  sealed  tube  from  which  the  air  has  been  expelled  by 
carbonic  anhydride.1  The  compound  may  also  be 
digested  on  the  water-bath  with  concentrated  potas- 
sium iodide  solution,  glacial  acetic  acid,  in  fairly  large 
quantity,  and  dilute  sulphuric  acid.'  When  the  re- 
action is  completed  the  liquid  is  titrated  with  N/io 
sodium  thiosulphate  solution  ;  no  indicator  is  required. 
Whenever  hydrochloric  acid  or  sulphuric  acid  has  been 
employed  in  the  reduction,  the  iodide,  which  is  pro- 
duced, always  retains  some  iodine  in  solution  hence, 
during  the  titration,  it  is  necessary  to  warm  and  shake 
the  liquid  until  this  has  all  been  acted  upon  by  the 
thiosulphate.  The  oxygen  percentage  content  of 
the  iodosy-  and  iodoxy-compounds  is  given   by  the 

o.8.c.  ioo  c 

formula  O  = =  0.08  —  ,  where  s  is  the  weight 

1000  s  s 

of  the   compound  taken   and  c  the  number  of  cc  of 

N/10  sodium  thiosulphate  employed. 


DETERMINATION  OF  THE  PEROXIDE  GROUP 


«} 


The  oxygen  of  the  acyl  superoxides  may  be  deter- 
mined by  means  of  stannous  chloride  in  acid  solution. 

1  V.  Meyer   and  Wachter,   B.   25,   2632.      P.   Askenasy  and  V. 
Meyer,  Ibid.  26,  1355,  et  seq. 

2  Willgerodt,  Ibid.  25,  3495,  et  seq. 

3  Pechmann  and  Vanino,  Ibid.  27.  1512. 


DETERMINATION   OF  THE   DIAZO   GROUP,  ETC.      Ill 

A  known  quantity  of  the  peroxide  is  heated  during 
about  five  minutes,  in  an  atmosphere  of  carbonic  an- 
hydride, with  a  measured  volume  of  a  titrated,  acidified 
stannous  chloride  solution.  When  the  liquid  is  clear 
the  remaining  stannous  chloride  is  determined  by 
means  of  N/io  iodine  solution. 

THE  IODINE  NUMBER.1 

This  value  expresses  the  quantity  of  iodine  absorbed 
by  one  hundred  parts  of  the  substance,  usually  a  fat 
or  higher  aliphatic  acid.  The  acids  of  this  series, 
such  as  oleic  acid,  ricinoleic  acid,  linoleic  acid  and 
linolenic  acid,  as  well  as  their  glycerides,  absorb  the 
first  two,  two,  the  others  four  and  six  atoms  of  iodine, 
bromine,  or  chlorine  respectively,  whilst  the  corre- 
sponding saturated  compounds,  under  similar  circum- 
stances, are  not  affected.  The  reaction  is  carried  out 
at  the  ordinary  temperature,  the  substance  being 
mixed  with  alcoholic  iodine  and  mercuric  chloride  solu- 
tions.2 The  organic  products  are  chloro-iodine  addi- 
tive compounds,  some  of  which  have  been  isolated  and 
characterized.3  The  method  is  extensively  employed 
in  the  technical  investigation  of  fats,  oils,  waxes, 
resins,  etheral  oils,  caoutchouc,  etc.,  and  is  some- 
times useful  for  scientific  purposes,  hence  a  brief  de- 
scription of  the  method  of  analysis  is  given  here. 


1  Benedikt,  "Analyse  d.  Fette  und  Wachsarten,"  III.  Edition, 
p.  148.  Allen,  "Commercial  Organic  Analysis,"  vol.  II,  3d  Edi- 
tion. 

2  Hiibl,  Dingl.  253,  281. 

3  R.  Henriques  and  H.  Kiinne.  B.  32,  389. 


112  RADICALS   IN   CARBON   COMPOUNDS. 

Reagents. 

(i)  Iodine  Solution.  Iodine  (25  grams)  and  mercuric 
chloride  (30  grams)  are  each  separately  dissolved  in 
95  per  cent  alcohol  (500  cc),  free  from  fusel  oil.  The 
mercuric  chloride  solution  is  filtered  if  necessary,  and 
the  liquids  mixed.  The  mixing  must  precede  the  use 
of  the  solution  by  6-12  hours  as,  during  this  period, 
the  titre  rapidly  changes. 

(2)  Sodium  TJiiosulpJiate  Solution.  The  crystallized 
salt  (24  grams)  is  dissolved  in  water  and  diluted  to  one 
liter.  It  is  standardized  in  the  following  manner:  ' 
Potassium  bichromate  (3.8740  grams)  is  dissolved  in 
water,  diluted  to  one  liter,  and  20  cc  of  the  liquid 
transferred  to  a  stoppered  bottle  containing  10  cc  of 
potassium  iodide  solution  (10  per  cent),  and  5  cc 
hydrochloric  acid  ;  the  liberated  iodine  is  then  titrated 
in  the  ordinary  manner  by  means  of  sodium  thiosul- 
phate,  starch  being  used  as  indicator;  1  cc  of  the  above 
bichromate  solution  liberates  O.oi  grams  of  iodine. 

(3)  Chloroform.  Its  purity  is  determined  by  a  blank 
experiment. 

(4)  Potassium  Iodide  Solution.  The  salt  is  dissolved 
in  ten  parts  of  water. 

(5)  Starch  Solution.  This  must  be  clear  and  recently 
prepared. 

Method  of  A  na lysis. 

The  substance  (o.  1  5-1 .0  gram)  is  mixed  with  chloro- 
form (about  10  cc)  in  a  500—800  cc  flask  provided  with 

1  Volhard. 


DETERMINATION   OF   THE   DlAZO    GROUP,  ETC.      113 

a  well-fitting  glass-stopper.  When  the  compound  has 
dissolved  the  iodine  solution  (25  cc)  is  added  by 
means#of  a  pipette  which  must  be  manipulated  so 
that  equal  quantities  are  delivered  in  each  experi- 
ment. The  flask  is  well  shaken  and  more  chloroform 
added  if  needful;  should  the  liquid  become  almost 
colorless  in  a  short  time  a  second  25  cc  of  iodine  solu- 
tion is  added,  and  this  repeated,  if  necessary  until, 
after  the  expiration  of  two  hours,  the  liquid  appears 
dark  brown.  The  mixture  is  now  allowed  to  remain 
during  twelve  hours  at  the  ordinary  temperature  in 
the  dark;  it  is  then  thoroughly  mixed  with  at  least 
20  cc  of  potassium  iodide  solution  and  300-500  cc 
of  water,  and  titrated  with  the  sodium  thiosulphate 
solution,  the  liquid  being  constantly  agitated ;  when 
only  a  faint  color  is  visible  in  both  the  aqueous  and 
chloroform  solutions,  starch  is  added  and  the  titration 
completed.  The  production  of  a  red  precipitate  of 
mercuric  iodide,  on  the  addition  of  water  before  the 
titration,  indicates  that  too  little  potassium  iodine 
has  been  employed,  but  this  may  be  corrected  by  the 
immediate  addition  of  more.  A  blank  experiment 
must  always  be  made  with  25  cc  of  the  iodine  solu- 
tion under  exactly  the  same  conditions  as  the  test, 
and  its  titration  must  immediately  precede  or  follow 
that  of  the  actual  determination. 

Useful  information  is  sometimes  given  by  the  tere- 
bcn  thene  n  u  mber. 1 

1  J.  Klimont,  Ch.  Ztg.  (1894),  No.  35,  37.     Ch.  R.  (1S94),  2,  2. 


APPENDIX. 


\6 


APPENDIX. 


WEIGHT    OF    A    CUBIC    CENTIMETER    OF    HYDROGEN 

PERATURE  OF   IO°-25°.1 

The  observed  height  of   the  barometer  is  reduced  to  o°  by 
and  2o"-25°  respectively. 


a  u- 


700 
702 
704 
706 
708 
710 
712 

714 

716 
718 
720 
722 
724 
726 
728 

730 

732 
734 
736 
738 
740 
742 

744 
746 
748 
750 

752 

754  |o. 

756  ,0 
758 

760 
762 

764 
766 
768 
770 


IO°C. 

mg 


n°  C. 


078510. 
078740. 
078960. 
079190. 
07942  o. 


12°  C. 

mg 


078160, 
078390. 
07861  |o. 

07884J0. 

079070. 

o7964!o. 079290. 


o. 


,07987 

08009 

08032 

08055 

0S078 

08101J0 

081230. 

o8i46|o. 

08169,0. 

08191  o. 

08215  o. 

08237:0. 

o8259|o. 

08282.0. 

08305  o. 

083280. 

083510. 

083730. 

083960. 

08419  o. 

08441  o. 

084640. 

0S487  o. 

08510.0. 

085330. 

085550 

.08578 

08601 
08624 


o. 

o, 

°' 

.08646  o. 


079520. 
079750. 
079970. 

080190. 
08043^. 
080650. 
080870. 
081 IOO. 
081330. 

08156  o. 

08  T  79O. 

08201  O. 

08224O. 

08246  o. 
082690. 
00291  o. 
083140. 
083370. 
083600. 
083820. 

08404  o. 

08428  o. 

084500. 

08472 

08496 

08518 

08541 

08563 

085S6 

08608 


07781 

07804 
07826 
07848 
07871 
07893 
07917 
07939 

07961 

07984 

08007 

08029 

08052 

08074 

08097 

08120 

08142 

08164 

081870 

08209 

08233 

08255 

08277 

08300 
08322 

08344 
08368 
0S390 

08413 

08435 

08458 

08481 

08503I0. 

08525:0 

085490 


TDg 


14°  C. 

rag 


O.077460. 

0.07769  o. 

o.o779i|o. 

o 

o 


o. 
o. 
(). 
o. 
o. 
0.08571 0 


078I3I0. 
078360. 

078580. 
07881:0. 
07903I0, 

,o7924jO. 
07948:0 

0797i|0- 

,079930, 

,08016  o. 

,08038 

,08061 

,08083 

08106 

08129 

08151 

08173 

08196 

0821S 

08240 

08263 

08285 

08308 

08331 

08353 
08376 
08398 
03420 
08443 
08465 
08487 
085 1 1 

08533 


rag 


077H 

07713 

07756 

07778 

078000 

07823 

07845 
,07868 
07890 
07912 

07935 

07957 

07979 

08002 

08024 

08047 

08069 

08091 

08114  O 

08136  O 

08T58 
08l8l 
08203 
08226 

08248J0 

082700 

08293:0 

08315I0 

0833S0 

083600 

083820 

08405^0 

08428 

08450 

08473 

08495I0 


07675 
07697 
07720 
07742 
07774 
07787 
07809 
07832 
07854 
07876 

07899 
07921 

07943 
07965 
07987 

08010 

08032 

08055 

08077J0 

080990 


[6°  C. 
mg 


07639 
07661 

.07684 
07706 
07729 

.07750 


0 

O.07772 

o 

o 
o 


07795 
.07817 

.07840 
07862 
.07SS4 
07907 
.07929 
■07951 
07973 
•07995 

.0S01S 
.08040 
08062 


>70C 
mg 


.08084 
>.o8io6Jo 

.08 1 29  !o 


08122  o. 
08144^0. 
081660, 

081890.08151,0, 
08211  o, 
08234  o, 
08256  o, 


.08 


,082780 
,08301,0 
,08323  o 

.083450 

08367  o 

08389 
08412 

08434 

08466 'o, 


730 

08195  o. 

082180. 

08240  o, 
082620. 
082850. 

08307  o. 
08329  o. 
08352  o. 
083740. 
083960. 
08418.0. 


07603 
07625 
07647 

07670 
07692 

07714 
07736 

07759 
07781 
07803 
07S25 
07847 

07869 

c/891 
(-7913 
07936 

07958 
07980 
08002 
08024 
08047 
08069 
08091 
08113 

08135 
08158 
08180 
08202 
08224 
0S246 
08269 
0S29I 
0S3I3 
08335 
08357 
08380 


A.  Baumann,  Z.  ang.  Ch.  1891,  210. 


APPENDIX. 


11/ 


UNDER    A    PRESSURE    OF   700-770   mm    AND    AT    A    TEM- 

u  ,          t    {&  ~  00)0.089523  \ 
Value  of   —r—. : TTT\     • 

760(1  4-  0.00366/)  J 
subtracting   I,  2,  or  3  mm  for  the   temperatures   io°-i2°,  I3°-I9°, 


i8°C. 

19°  C. 

20°  C. 

21°  C. 

22°  C. 

23°  C. 

24"  C. 

25°  C 

mg 

mg 

rag 

mg 

mg 

mg 

mg 

mg 

mm 

O.07557 

O.07529 

O.07493 

O.07455 

O.07417 

O.07380 

O.07340 

O.0730O 

700 

O.07588 

0.07552 

007515 

O.07477 

O.07439 

O.074OI 

O.07362 

O.07322 

702 

O.07610 

O  07574 

O.07537 

O.07499 

O.07461 

O.07422 

O.07383 

O.07344 

704 

O.07633 

O.07595 

O.07559 

O.07521 

O.07483 

O.07444 

O.07405 

O.07366 

706 

O.07655 

O.07618 

O.075S1 

O.07543 

O.07505 

O.07466 

O.07427 

O.07387 

708 

O.07677 

O.07640 

O.07603 

O.07565 

O.07527 

O.07487 

O.07449 

O.07409 

7IO 

O.07699 

O.07662 

O.07625 

O.07587 

O.07548 

O.07509 

O.07470 

O.07431 

712 

O.07722 

O.07684 

O.07646 

O.07608 

O.07570 

O.07531 

O.07492 

O.07452 

714 

O.07743 

O.07706 

O.07668 

O.07630 

O.07592 

O.07553 

0.075I3 

O.07473 

716 

O.07765 

O.07728 

O.0769O 

O.07652 

O.07614 

O.07574 

O.07535 

O.07495 

718 

O.07788 

0.07749 

O.07712 

O.07674 

O.07635 

O.07596 

O  0755O 

O.07516 

720 

O.07809 

O.07772 

O.07734 

O.07696 

O.07657 

O.07618 

O.07577 

O.07538 

722 

O.07831 

O.07794 

O.07756 

0.0771-8 

O.07679 

O.07640 

O.07609 

O.07560 

724 

O.07854 

O.07816 

O.07778 

O  07740 

O.07701 

O.07661 

O.07621 

O.07582 

726 

O.07876 

O.07838 

O.07S00 

O.07762 

O.07723 

O.07683 

O.07643 

O.07604 

728 

O.07908 

O.07860 

O.07822 

O.07784 

O.07744 

O.07705 

O.07665 

O.07624 

73o 

O.07920 

O.07882 

O.07844 

0.07805 

O.07766 

O.07727 

O.07687 

O.07646 

732 

O.07942 

O.07904 

O.07866 

O.07827 

O.07780 

O.07748 

O.07708 

O.07668 

734 

O.07964 

O.07926 

O.07888 

O.07849 

0.07810 

O.07770 

O.07730 

O.07689 

736 

O.07986 

O.07948 

O.07910 

O.07871 

O.07831 

O.07792 

O.07752  O.07711 

738 

O.08009 

O.07970 

O.07932 

O.07893 

O.07853 

O.07813 

O.077740.07732 

740 

O.08030 

O.07992 

O.07954 

O.07915 

O.07875 

O.07835 

O.077950.07754 

742 

O.08053 

O.08014 

O.07976 

O.07937 

O.07897 

O.07857 

O.07817  O.07776 

744 

0.0S075 

O.08036 

O.07998 

O.07959JO.07919 

O.07879 

O.07838 

0.07797 

746 

0.08097 

O.08058 

O.08020 

0  07981  0.07940 

O.07900 

O.07860 

O.07819 

748 

O.0S119 

O.08080 

O.08042 

0.08002  O.07962 

O.07922 

O.07881 

O.0784O 

75o 

O.08141 

O.08102 

O.08063 

O.08024  O.07984 

O.07944 

O.07903 

O.07862 

752 

O.08163 

O.08124 

O.08085 

O.08046  O.08006 

O.07966 

O.07925 

O.07883 

754 

O.08185 

O.08146 

O.08107 

O.08068 

O.08028 

O.07987 

O.07947 

O.07905 

756 

O.08207 

O.08168 

O.08129 

O.0809O 

O.08050 

O.08009 

O.07968 

O.07927 

758 

O.08229 

O.0819O 

O.08151 

O.o8ll2 

O.08071 

O.08031 

O.07990 

O.07949 

760 

O.08251 

0.082I2 

O.08173 

O.08134 

O.08093 

O.08052 

O.08012 

O.07970 

762 

O.0S273 

O.08234 

O.08195 

O.08155 

0  081 15 

O.08074 

O.08033 

O.07992 

764 

O.08295 

O.08256 

O.08217 

O.08177 

O.08137 

O.08096 

O.08055 

O.08013 

766 

O.083181 

O.08278 

O.08239 

O.08199  O.0S158 

O.08118 

O.08076 

O.08034 

768 

O.08341 

O.08301 

O.08261 

0.OS22I, 

O.08180 

O.08139 

O.08098 

O.08056 

770 

n8 


APPENDIX. 
TENSION  OF  AQUEOUS  VAPOR. 


o°C. 

mm 

o°C. 

mm 

IO.O 

9.165 

18.0 

15.357 

10.5 

9-474 

18.5 

15.845 

II. 0 

9.792 

19.0 

16.346 

11. 5 

10. 120 

19-5 

16.861 

12.0 

10-457 

20.0 

I7-39I 

12.5 

10.804 

20.5 

17-935 

13-0 

11. 162 

21.0 

18.495 

13-5 

11.530 

21.5 

19.069 

14.0 

1 1 . 908 

22.O 

19.659 

14.5 

12.298 

22.5 

20. 265 

15.0 

12.699 

23.O 

20.888 

15-5 

13.112 

23-5 

21.528 

16.0 

I3.536 

24.0 

22.184 

16.5 

13-972 

24-5 

22.858 

17.0 

14.421 

25.0 

23-550 

17.5 

14.882 

TABLE  FOR  THE  VALUE  OF 


999. 


0 

1 

■ 

3 

4 

"  s 

6 

7 

8 

9 

00 

O . OOOO 

010 

020 

030 

040 

050 

060 

071 

08l 

091 

01 

101 

in 

122 

132 

142 

152 

163 

173 

I83 

194 

02 

204 

215 

225 

235 

246 

256 

267 

278 

288 

299 

03 

309 

320 

33i 

34i 

352 

363 

373 

384 

395 

406 

04 

417 

428 

438 

449 

460 

47i 

482 

493 

504 

515 

05 

526 

537 

549 

560 

57i 

582 

593 

605 

616 

627 

06 

638 

650 

661 

672 

684 

695 

707 

718 

730 

74i 

07 

753 

764 

776 

788 

799 

811 

823 

834 

846 

858 

08 

0.0870 

881 

893 

905 

917 

929 

941 

953 

965 

977 

09 

989 

*OOI 

*oi3 

*025 

*o38 

*o5o 

*o62 

*o74 

*o87 

*099 

10 

O.IIII 

124 

136 

148 

151 

173 

186 

198 

211 

223 

II 

236 

249 

261 

274 

287 

299 

312 

325 

338 

35i 

12 

364 

377 

390 

403 

416 

429 

442 

455 

468 

481 

13 

494 

508 

528 

534 

547 

564 

574 

588 

601 

614 

14 

628 

641 

655 

669 

682 

696 

710 

723 

737 

751 

15 

765 

779 

793 

806 

820 

834 

848 

862 

877 

891 

16 

905 

919 

933 

947 

962 

976 

990 

*oo5 

*oi9 

*o34 

17 

0.2048 

083 

o77 

092 

107 

121 

13b 

151 

166 

180 

18 

195 

210 

225 

240 

255 

270 

285 

300 

315 

33i 

19 

346 

361 

376 

392 

407 

422 

438 

453 

469 

484 

Obach— Ostwald,  Z.  II.  566. 


APPENDIX. 
TABLE  FOR  THE  VALUE  OF  - 


II9 


{Continued.) 


0 

1 

2 

3 

4 

5 

6 

7 

8 

9 

20 

0.2500 

516 

53i 

547 

563 

579 

595 

610 

626 

642 

21 

658 

674 

690 

707 

723 

739 

755 

771 

788 

804 

22 

821 

837 

854 

870 

887 

903 

920 

937 

953 

970 

23 

987 

*oo4 

*02I 

*o38 

*055 

*072 

*o89 

*io6 

*I23 

*I4I 

24 

0.3158 

175 

193 

210 

228 

245 

263 

280 

298 

316 

25 

333 

35i 

369 

387 

405 

423 

441 

459 

477 

495 

26 

514 

532 

550 

569 

587 

605 

624 

643 

661 

680 

27 

699 

717 

736 

755 

774 

793 

812 

831 

850 

870 

28 

889 

908 

928 

947 

967 

986 

*oo6 

*025 

*045 

*o65 

29 

0.4085 

104 

124 

144 

164 

184 

205 

225 

245 

265 

30 

286 

306 

327 

347 

365 

389 

409 

430 

45i 

472 

31 

493 

514 

535 

556 

577 

599 

620 

641 

663 

684 

32 

706 

728 

749 

771 

793 

815 

837 

859 

881 

903 

33 

925 

948 

970 

993 

*oi5 

*038 

*o6o 

*o83 

*io6 

*I2g 

34 

0.5152 

175 

198 

221 

244 

267 

291 

314 

337 

361 

35 

385 

408 

432 

456 

480 

504 

528 

552 

576 

601 

36 

625 

650 

674 

699 

721 

748 

773 

798 

813 

848 

37 

873 

898 

924 

949 

974 

*ooo 

*026 

*o5i 

*o77 

*i63 

38 

0.6129 

155 

181 

208 

234 

260 

287 

313 

340 

367 

39 

393 

420 

447 

475 

502 

529 

556 

584 

611 

639 

40 

667 

695 

722 

75o 

779 

807 

835 

863 

892 

921 

4i 

949 

978 

*oo7 

*036 

*o65 

*094 

*I23 

*I53 

*I82 

*2I2 

42 

0.7241 

271 

301 

33i 

361 

39i 

422 

452 

483 

513 

43 

544 

575 

606 

637 

668 

699 

731 

762 

*794 

825 

44 

857 

889 

921 

953 

986 

*oi8 

*o5i 

*o83 

116 

45o 

*I49 

45 

0.8182 

215 

248 

282 

315 

349 

382 

416 

484 

46 

519 

553 

587 

622 

657 

692 

727 

762 

797 

832 

47 

868 

904 

939 

975 

*OII 

*o48 

*o84 

*I2I 

*I57 

*i94 

48 

0.9231 

268 

305 

342 

380 

418 

455 

493 

53i 

57o 

49 

608 

646 

685 

724 

763 

802 

841 

881 

920 

960 

50 

1. 000 

004 

008 

012 

016 

020 

024 

028 

033 

037 

51 

041 

045 

049 

053 

058 

062 

066 

070 

o75 

079 

52 

083 

088 

092 

096 

IOI 

105 

no 

114 

119 

123 

53 

128 

132 

137 

141 

146 

151 

155 

160 

165 

169 

54 

174 

179 

183 

188 

193 

198 

203 

20S 

212 

217 

55 

222 

227 

232 

237  1  242 

247 

252 

257 

262 

268 

56 

273 

278 

283 

288  i  294 

299 

304 

309 

315 

320 

57 

326 

33i 

336 

342  ;  347 

353 

358 

364 

37o 

375 

58 

38i 

387 

392 

398  j  404 

410 

415 

421 

427 

433 

59 

439 

445 

45i 

457  '  463 

469 

475 

484 

488 

494 

120 


APPENDIX. 


TABLE  FOR  THE  VALUE  OF 


:ooo  —  a 


{Continued.) 


0 

1 

2 

3 

4 

s 

6 

7 

8 

9 

60 

1.500 

506 

513 

519 

525 

532 

538 

545 

551 

556 

61 

564 

571 

577 

584 

59i 

597 

604 

611 

618 

625 

62 

632 

639 

646 

653 

660 

667 

674 

681 

688 

695 

63 

703 

710 

717 

725 

732 

740 

747 

755 

762 

77o 

64 

77S 

786 
865 

793 

801 

S09 

817 

825 

833 

841 
924 

849 

65 

857 

874 

8S2 

890 

899 

907 

9i5 

933 

66 

941 

950 

959 

967 

9"/6 

985 

994 

*oo3 

*OI2 

"021 

67 

2.030 

040 

049 

058 

067 

o77 

086 

096 

I06 

115 

68 

125 

135 

145 

155 

165 

175 

185 

195 

205 

215 

69 

226 

333 

236 

247 

257 
367 

268 

279 

289 

300 
413 

311 

425 

322 

70 

344 

356 

378 

390 

401 

436 

7i 

448 

460 

472 

484 

497 

509 

521 

534 

546 

559 

72 

57i 

584 

597 

610 

623 

636 

650 

663 

676 

690 

73 

704 

717 

73i 

745 

759 

774 

788 

802 

817 

831 

74 

846 

861 

876 

891 

906 

922 

937 
098 

953 

968 

984 

75 

3.000 

016 

032 

049 

065 

082 

ii5 

132 

149 

76 

167 

184 

202 

219 

237 

255 

274 

292 

3IO 

329 

77 

348 

367 

^86 

405 

425 

444 

464 

484 

505 

525 

78 

545 

566 

587 

608 

630 

651 

673 

695 

717 

739 

79 

762 

785 

808 

831 

854 

878 

902 

926 

950 

975 

80 

4.000 

025 

051 

076 

102 

128 

155 

181 

208 

236 

81 

263 

291 

319 

348 

376 

405 

435 

465 

495 

525 

82 

556 

587 

618 

650 

682 

7*4 

747 

780 

814 

848 

83 

882 

917 

952 

988 

*024 

*o6i 

♦098 

*135 

*I73 

*2II 

84 

5-250 

289 

329 

369 

410 

452 

494 

536 

579 

623 

85 

667 

711 

757 

803 

849 

897 

944 

993 

*042 

*og2 

86 

6.143 

194 

246 

299 

353 

407 

463 

519 

576 

654 

«7 

692 

752 

813 

874 

937 

*ooo 

*o65 

*i30 

*i97 

^264 

88 

7-333 

403 

475 

547 

62  r 

696 

772 

850 

929 

*oo9 

89 

8.091 

174 

259 

346 
309 

434 
417 

524 

615 

769 

753 

804 
870 

901 

90 

9  000 

101 

204 

526 

638 

989 

9i 

10. 11 

io.33 

10.36 

10.49 

10.63 

10.77 

10.90 

11.05 

11.20 

ii-35 

92 

11.50 

11.66 

11.82 

11.99 

12. 16 

12.33 

12.51 

12.70 

12.89  x3  °8 

93 

13.29 

13-49 

I3.7I 

13-93 

14.15 

14.38 

14.63 

14.87 

15.13  15.39 

94 

15.67 

15.95 

16.24 

16.54  16.86 

17.18 

17.52 

17.87 

18.23  18.61 

95 

19.00 

19.41 

19.83 

20.28  20.74 

21.22 

21.73 

22.26 

22. 81,23.39 

96 

24.00 

24.64 

25.32 

26.03  26.78 

27-57 

28.41 

29.30 

30.25  31-26 

97 

32.33 

33.4834.71 

36.04 

37-46 

40.67 

42.48 

44.4546.62 

98 

49.00 

51.6 

54-6  1 

57-8 

61.5 

65.7 

70.4 

75-9 

82.3  89.9 

99 

99.0 

no 

124  1 

142 

166  1 

199  1 

249 

332 

499  !  999 

INDEX   OF   AUTHORS. 


Allen,  A.  H in 

Anderlini 4,  61 

Angeli,  A 88 

Askenasy ,  P no 

Auwers,  K , 72 

B 

Baeyer,  A.  v 74,77,78 

Bamberger,  E 19,  62,  64,  72,  103 

Bamberger,  M 35,37 

Barth 12,  20 

Barus 46 

Baum 62,  74 

Baumann 18,  57,  59,  116 

Beckmann 8,  32,  40 

Benedikt 4,  10,  35,  36,  37,  65,  68,  in 

Berthelot,  D 50 

Biginelli 74 

Blau,  Fr 82 

Boeris 99 

Bouveault 91 

Buchka 4,  15 


C 

Cahart 50 

Cahn,  A 80 

121 


122  INDEX   OF  AUTHORS. 

Cain 90 

Cavazzi 88 

Ciamician 14,  99 

Claisen,  L 6,  20,  22,  23 

Claus 74,  91 

Cohen,  E 47 

Collie,  N 89 

Crismer 73 

Curtius 86,  ioo,  101,  102,  105 


D 

Danck  worth 10,  18 

Davies 74 

Dedichen 86 

Delepine 83 

Deninger,  A 6,  21 

Diamant,  J 8 

Dobriner,  P 17 

E 

Ebert 49 

Eckhardt 42 

Ehmann,  L 35 

Elbers 62 

Ephraim 62 

Erb 9°.  91 

Erdmann 11,  15,  3° 

Erk 15 

Erlich 4 

F 

Feist 6,  21 

Feit 74 

Feitler 88 

Fischer,  E 45,60,63,64,93 

Franchimont 8 

Fresenius 15 

Freund 45 


INDEX   OF  AUTHORS.  1 23 

Frobenius 103 

Fuchs,  F 52,  56 


Garelli 73 

Gattermann 29,  87,  88,  109 

Ghiro 4 

Giraud,  H 93 

Goldschmidt,  H 103 

Goldschmiedt 12,  14,  17,  20,  21,  31,  51 

Graebe 4,  28 

Grandmougin 86 

Green,  A.  G 85 

Gregor,  J 39 

Griess,  P 86 

Groger,  M 59 

Griissner 35 

Gumpert 32 

Guyot 28 


H 

Hagen 44.  45 

Haitinger 43 

Haller 28 

Hautzsch 91,  103 

Harpe,  De  la 84,  93 

Harries,  C 74 

Hawkins 86 

Hemmelmayr 14,  17,  21,  51,  62 

Henriques,  R ill 

Herzfeld 13,  80 

Herzig,  J 5,  n,  14,  15,  28,  38,  73,  94,  99 

Heuser 75 

Heyl,  G 92 

Hinsberg 24,  27 

Hirsch,  R 85 

Hoffmann,  C 74 

Hoffmann,  E 20 

Hofmann,  A.  W 31,  89,  90 


124  INDEX   OF   AUTHORS. 

Holle 62 

Hollemann 104 

Homolka 42,  71 

Hormann,  O 7 

Hiibl in 

Huth 30 

Hyde,  E 64 


I 
Iritzer,  S 104,106 


J 

Jackson,  F.  L 23 

Jacobson,  P 29,  80,  90,  92 

Janny 70 

Jassoy 27 

Jeaneraud 74 

Jehn,  C 52 

Jenssen 107 

Jones,  H 46 

Just 62 


K 

Kehrmann 72,  73 

Kinnicutt,  L.  P 86 

Klimont,  J 113 

Klobukowsky 8,  11 

Knoevenagel 103 

Knop 57 

Knorr 26 

Kohlrausch 47 

Kormann,  W 81 

Kostanecki 28,  73 

Kraus 64 

Kruger 64,  77 

Kunne,  H in 

Kux 57 


INDEX   OF  AUTHORS.  125 


L 

La  Coste 8 

Landsiedl 5 

Lassar-Cohn 42 

Lehmann 74 

Lieben 10,12,43 

Liebermann,  C 7.  14,  21,  44,  45 

Limpricht,  H 106 

Lossen 18,  19 

Lucas 91 


M 

Mcllhiney,  P.  C 52 

Marchlewsky 28 

Meldola 86 

Menschutkin 83 

Merz,  A 103 

Meyer,  E.  v 106 

Meyer,  H 16,  25,  38,  57,  94,  99/104 

Meyer,  R 16,  25,  62 

Meyer,  V 20,  29,  44,  62,  70,  74,  80,  90,  91,  92,  no 

Meyer 42 

Michael,  H.  A 8,  16 

Michaelis 63 

Michel,  0 86 

Munch 91 

Munchmeyer 62 

N 

Nef ,  J.  U 63,  74,  86 

Neufeld,  A 65 

Nietzki 72 

Nolting 86 

O 

Obach 118 

Ostwald,  W 46,  48,  118 


126  INDEX   OF  AUTHORS. 

otto : .  23 

Overton,  B 61,  63 

Overton,  R 65 


P 

Panormow 18 

Patterson 50 

Pechmann,  v 18,  28,  62,  103,  no 

Perkin,  W.  H.,  Sen 28 

Perkin,  W.  H.,  Jun 42 

Petersen 104,  105 

Petraczek 71 

Pomeranz 38 

Pum,  G 24,  37 


R 

Radziszewski gi 

Raschig 73 

Regnault 103 

Re verdin 84,  93 

Richards,  T.  W 44 

Rideal,  S 85 

Rolfe,  G.  W 23 


S 

Sachsse 81 

Sandmeyer 87 

Sarauw 4 

Saul,  E 62 

Schall 15 

Schiaparelli,  C 24 

Schiff 5,  12,  14 

Schlomann 22,  24 

Schmidt,  G 29 

Schmiedeberg 42 

Schmolge  • 13 

Schopf 22 

Schotten 22,  23,  24 


INDEX   OF   AUTHORS.  \2J 

Schreder 20 

Schultz 11 

Schulze • 15 

Schunk 28 

Schiitzenberger 13 

Seelig 5,  62,  72,  91 

Silber 14 

Sisley,  P 16 

Skraup 19 

Smith,  Alex 42 

Smoeger 13 

Snape 31,  32 

Speier 45 

Stange 75 

Stallburg 90 

Strache,  H 65,  68,  104,  106 

Strouhal 46 

Sudborough 90,  9T,  92 

Swain,  R.  E 107 

T 

Taf  el 63 

Tessmer $1,  32 

Thiele 74.  75,  78,  79 

Thompson 22,  23 

Thorns 62 

Thorp 72 

Tickle,  T 89 

Tiemann,  F 64,  71,  77 

Tingle,  A   45,63 

Tingle,  J.  Bishop 45,  63,  74 

U 
Ulzer 10 


V 

Valden 46 

Valeur 8 


128  INDEX   OF  AUTHORS. 

Vanin no 

Vohl 52 

Volhard 40,71,112 

Vongerichten 26,  32 

Vortmann n 

Vries,  de . 104 

W 

Wachter no 

Wagner 57 

Wallbaum 91 

Wiedemann 49 

Willgerodt no 

Wislicenus 6,  14 

Wohl 71 

Wolff 80 

Wright 10 

Y 

Young,  S.  W 107 

Z 

Zanoli . 31 

Zeisel.S 10,  12,  28,  33,  37,  38,  41,  73 


INDEX   OF   SUBJECTS. 


A 

Acetic  acid 3 

glacial 5 ,  8 

anhydride 5,7 

Acetylation,  methods  of 5 

Acetyl  chloride 5,  6 

derivatives,  isolation  of 9 

preparation  of 5 

groups,  determination  of 9 

(additive  method) 14 

(distillation  method) 15 

(potassium  acetate  method)..      14 

Acids,  electrolytic  conductivity  of 46 

etherification  of 44 

titration  of  43 

Acylation 3 

Aliphatic  amino  groups,  determination  of 81 

diazo-compounds 100 

Alkylation 3 

of  hydroxyl  groups 28 

Amidodimethylaniline  (/)  derivatives 80 

group,  determination  of 91 

guanidine  derivatives,  preparation  of 78 

picrate  derivatives,  preparation  of 80 

salts,  preparation  of 78 

Amines,  acetylation  of 83,  89 

salts  of 82,  89 

Amino  groups,  determination  of 81 

Aqueous  vapor,  tension  of 118 

129 


130  INDEX  OF  SUBJECTS. 

Aromatic  amino  groups,  determination  of 83 

diazo-compounds 103 

Authors,  index  of 121 

Azoinide  method,  for  determination  of  amino  group 86 

B 

Barium  hydroxide,  hydrolysis  by 9,  n 

Basicity  of  acids,  determination  of  by  ammonia  method 52 

carbonate  method 51 

hydrogen  sulphide  method     52 

iodine-oxygen  method 57 

Benzene  and  water,  tension  of 68 

Benzoic  acid 3 

acids,  substituted 3 

anhydride 17,  21 

Benzoyl  chloride 17,  18 

derivatives,  analysis  of 24 

preparation   of 17 

Benzyl  derivatives 28 

/^-Brornbenzoic  anhydride 17,  22,  23 

<?-Brombenzoyl  chloride 17,  22,  23 

^-Brombenzoyl  chloride 17,  22,  23 

C 

Carbamates 3 

preparation  of 29 

Carbamyl  chloride,  preparation  of 29 

Carbonyl,  determination  of 60 

Carboxyl,  determination  of 41 

indirect , 65 

Chloracetyl  chloride 5,  8 

1:2:  4-Chlorodinitrobenzene 32 

Cyanide  group,  determination  of 90 

D 

Diazo-compounds,  aliphatic 100 

aromatic 103 

preparation  of 84 

group,  determination  of 100 


INDEX   OF   SUBJECTS.  131 

Diazonium  derivatives 103 

Diazomethane  as  reagent  for  hydroxyl •  •  •  •     28 

Diphenylcarbamyl  chloride,  preparation  of 30 

E 

Electrolytic  conductivity  of  sodium  salts 46 

Etherification  of  acids 44 

Ethoxyl,  determination  of 41 

and  methoxyl,  differentiation  of 40 

Ethylimide  and  methylimide,  differentiation  of ,  99 

Ethylimide,  determination  of 99 

G 

Gattermann-Sandmeyer's  reaction 87 

H 

Hydrazide  group,  determination  of 103 

Hydrazides,  oxidation  of 104 

Hydrazones,  substituted,  preparation  of 63.  64 

Hydrochloric  acid,  hydrolysis  by 10,  13 

Hydrogen,  weight  of  a  cc  of 116 

Hydriodic  acid,  hydrolysis  by 10,  14 

Hydrolytic  methods  for  determination  of  acetyl  groups 9 

Hydroxyl,  determination  of 3 


I 

Imide  group,  determination  of 92 

Imides,  acetylation  of 92 

alkylation  of 93 

salts  of '....,....  94 

Index  of  authors 121 

subjects 129 

Introduction I 

Iodine  number ill 

Iodoso-group,  determination  of 109 

Iodoxy-group,  determination  of 109 

Isobutyric  acid 3 

anhydride 27 

Isobutyryl  derivatives 27 


132  INDEX   OF   SUBJECTS. 


M 


Magnesia,  hydrolysis  by 10,  12 

Metanitrobenzoyl  chloride 17,  22,  23 

Methoxyl,  determination  of  (Zeisel's  method) 33 

modified 39 

and  ethoxyl,  differentiation  of 40 

Methylimide  and  ethylimide,  differentiation  of 99 

determination  of 94 

determination  of  in  presence  of  methoxyl 97 


N 

Nitrile  group,  determination  of 90 

w-Nitrobenzoyl  chloride 17,  22,  23 

Nitro-group,  determination  of 106 

O 

Orthobromobenzoyl  chloride 17,  22,  23 

Oximes,  preparation  of 70 

P 

Paramidodimethylaniline  derivatives 80 

Parabrombenzoic  anhydride 17,  22,  23 

Parabrombenzoyl  chloride 17,  22,  23 

Parabromphenylhydrazine,  preparation  of 63 

Peroxide  group,  determination  of no 

Phenylacetic  acid 3 

Phenylacetyl  chloride 27 

Phenylcarbamic  acid  derivatives,  preparation  of 31 

Phenylcarbamates 3 

Phenylhydrazones,  preparation  of 60 

substituted,  preparation  of 63,  64 

Phenylisocyanate,  action  of,  on  hydroxyl 31 

preparation  of 31 

Phenylsulphonic  acid 3 

chloride 17,  23,  24 

Phosphoric  acid  as  reagent 15 

Phosphoric  acid  derivatives 27 


INDEX    OF   SUBJECTS.  133 

Potassium  hydroxide,  hydrolysis  by 9»  IO 

hydroxylamine  sulphonate  as  reagent 73 

Propionic  acid 3 

anhydride 27 

Propionyl  derivatives 27 

S 

Salts  of  acids,  analysis  of 42 

bases,'  preparation  of 82,  83 

Sandmeyer-Gattermann's  reaction 87 

Semicarbazide  salts,  preparation  of 75 

Semicarbazones,  preparation  of 74,  77 

Sodium  acetate 5»  7 

benzoate I7>  21 

hydroxide,  hydrolysis  by 9,  10 

Stearic  anhydride 27 

Substituted  benzoic  acids 17,  22,  23 

acylation  by  means  of 23 

hydrazones,  preparation  of 63,  64 

phenylhydrazones,  preparation  of 63,  64 

Sulphuric  acid,  hydrolysis  by 10,  13 


T 

Tables 1 16  et  seq. 

Table  of  tension  of  benzene  and  water 68 

water 118 

weight  of  a  cc  of  hydrogen 116 

W 

Water,  hydrolysis  by   9,  10 

Water  and  benzene,  table  of  tension  of 68 

hydrolysis  by 9,  10 

table  of  tension  of 118 


SHORT-TITLE    CATALOGUE 

OF  THE 

PUBLICATIONS 

OF 

JOHN   WILEY   &    SONS, 

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1 


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LIBRARY,  UNIVERSITY  OF  CALIFORNIA,  DAVIS 

Book  Slip-35m-7,'62(D296s4)458 


M 


2U7671 


Meyer,  H.J.L. 

Determination  of 
radicles  in  carbon 


/er 


Call  Number: 

QD271 
M6l 


Ml  CI 


247671 


